• Announcements

    • UnderDawg

      A Few Simple Rules   05/22/2017

      Sailing Anarchy is a very lightly moderated site. This is by design, to afford a more free atmosphere for discussion. There are plenty of sailing forums you can go to where swearing isn't allowed, confrontation is squelched and, and you can have a moderator finger-wag at you for your attitude. SA tries to avoid that and allow for more adult behavior without moderators editing your posts and whacking knuckles with rulers. We don't have a long list of published "thou shalt nots" either, and this is by design. Too many absolute rules paints us into too many corners. So check the Terms of Service - there IS language there about certain types of behavior that is not permitted. We interpret that lightly and permit a lot of latitude, but we DO reserve the right to take action when something is too extreme to tolerate (too racist, graphic, violent, misogynistic, etc.). Yes, that is subjective, but it allows us discretion. Avoiding a laundry list of rules allows for freedom; don't abuse it. However there ARE a few basic rules that will earn you a suspension, and apparently a brief refresher is in order. 1) Allegations of pedophilia - there is no tolerance for this. So if you make allegations, jokes, innuendo or suggestions about child molestation, child pornography, abuse or inappropriate behavior with minors etc. about someone on this board you will get a time out. This is pretty much automatic; this behavior can have real world effect and is not acceptable. Obviously the subject is not banned when discussion of it is apropos, e.g. talking about an item in the news for instance. But allegations or references directed at or about another poster is verboten. 2) Outing people - providing real world identifiable information about users on the forums who prefer to remain anonymous. Yes, some of us post with our real names - not a problem to use them. However many do NOT, and if you find out someone's name keep it to yourself, first or last. This also goes for other identifying information too - employer information etc. You don't need too many pieces of data to figure out who someone really is these days. Depending on severity you might get anything from a scolding to a suspension - so don't do it. I know it can be confusing sometimes for newcomers, as SA has been around almost twenty years and there are some people that throw their real names around and their current Display Name may not match the name they have out in the public. But if in doubt, you don't want to accidentally out some one so use caution, even if it's a personal friend of yours in real life. 3) Posting While Suspended - If you've earned a timeout (these are fairly rare and hard to get), please observe the suspension. If you create a new account (a "Sock Puppet") and return to the forums to post with it before your suspension is up you WILL get more time added to your original suspension and lose your Socks. This behavior may result a permanent ban, since it shows you have zero respect for the few rules we have and the moderating team that is tasked with supporting them. Check the Terms of Service you agreed to; they apply to the individual agreeing, not the account you created, so don't try to Sea Lawyer us if you get caught. Just don't do it. Those are the three that will almost certainly get you into some trouble. IF YOU SEE SOMEONE DO ONE OF THESE THINGS, please do the following: Refrain from quoting the offending text, it makes the thread cleanup a pain in the rear Press the Report button; it is by far the best way to notify Admins as we will get e-mails. Calling out for Admins in the middle of threads, sending us PM's, etc. - there is no guarantee we will get those in a timely fashion. There are multiple Moderators in multiple time zones around the world, and anyone one of us can handle the Report and all of us will be notified about it. But if you PM one Mod directly and he's off line, the problem will get dealt with much more slowly. Other behaviors that you might want to think twice before doing include: Intentionally disrupting threads and discussions repeatedly. Off topic/content free trolling in threads to disrupt dialog Stalking users around the forums with the intent to disrupt content and discussion Repeated posting of overly graphic or scatological porn content. There are plenty web sites for you to get your freak on, don't do it here. And a brief note to Newbies... No, we will not ban people or censor them for dropping F-bombs on you, using foul language, etc. so please don't report it when one of our members gives you a greeting you may find shocking. We do our best not to censor content here and playing swearword police is not in our job descriptions. Sailing Anarchy is more like a bar than a classroom, so handle it like you would meeting someone a little coarse - don't look for the teacher. Thanks.
    • B.J. Porter

      Moderation Team Change   06/16/2017

      After fifteen years of volunteer moderation at SA, I will no longer be part of the moderation team. The decision to step aside is mine, and has been some time in the works but we did not wish to announce it in advance for a number of reasons. It's been fun, but I need my time back for other purposes now. The Underdawg admin account will not be monitored until further notice, as I will be relinquishing control of it along with my administrative privileges. Zapata will continue on as a moderator, and any concerns or issues can be directed to that account or to the Editor until further notice. Anyone interested in helping moderate the forums should reach out to Scot by sending a PM to the Editor account. Please note that I am not leaving the community, I am merely stepping aside from Admin responsibilities and privileges on the site.
Wess

Proa question

438 posts in this topic

I must be nuts to ask this here - the proa debates have always seemed odd to me - but here it goes.

 

So if I understand correctly...

 

The Atlantic proa has the weight and rig to windward and gets its stability from the buoyancy of the leeward hull. Essentially a trimaran without the windward float. Greats like Newick designed iconic boats like Cheers which are of this type.

 

The Pacific proa has the weight and rig to leeward and gets its stability from the righting moment of the windward hull (which might incorporate water ballast). Essentially a trimaran without the leeward float with a smaller windward float. Greats like Brown designed iconic boats like Jzerro which are of this type.

 

People have been fighting over the type ever since but given the greats involved on both sides perhaps we can reasonably say each has merits?

 

Then along come Rob Denny and essentially splits the middle with the Harryproa which has the weight to windward but the rig to leeward. Forgive me Rob, but please allow me without passing judgment, to ignore this type for the moment.

 

Here is what I don't understand about the Atlantic/Pacific thing...

 

A oversimplification for sure but part of the benefit of the proa is that you have greater speed potential than the tri because the weight of unused float is dispensed with along with the build time and costs for that part of the structure. But in place of simply tacking or gybing we now have this new type of a maneuver called shunting. So here is the question...

 

Why can't a proa be designed to be sailed in both Atlantic and Pacific mode and the transition between the two - instead of shunting - would be this simple traditional maneuver called a tack or gybe? Why not just tack Cheers, add water ballast and sail her in "Pacific" mode on the new tack... or is the rig and board locations giving me horribly unbalance helm when I do that?

 

Flame suit on and ready.

 

Ducking...

 

Wess

 

 

 

 

Share this post


Link to post
Share on other sites

The Pacific proa has the weight and rig to leeward and gets its stability from the righting moment of the windward hull (which might incorporate water ballast). Essentially a trimaran without the leeward float with a smaller windward float. Greats like Brown designed iconic boats like Jzerro which are of this type.

 

It's not the weight of the windward hull alone. The mast, cockpit, engine and "heavy stuff" in the main hull, positioned to windward, all contribute to moving the CG (Center of Gravity) to windward - before any water ballast is added.

 

 

People have been fighting over the type ever since but given the greats involved on both sides perhaps we can reasonably say each has merits?

 

Then along come Rob Denny and essentially splits the middle with the Harryproa which has the weight to windward but the rig to leeward. Forgive me Rob, but please allow me without passing judgment, to ignore this type for the moment.

 

Civil discussions degenerated into fighting when Denney showed up and immediately started attacking the Pacific proa idea (weight to leeward), seeing no merit at all, despite two+ decades of Russell Brown's proven work (cover of Wooden Boat Magazine, summer of 1988):

 

wb-1.jpg

 

 

Denny began a relentless campaign of insults, lies and absurd claims about his better, cheaper and faster design. After only ten days, I said this (30 Aug 1999):

 

I believe, Rob, it is too much effort to sort out the reality behind the myth, especially when it doesn't bother you at all to make bold statements that you must later retract. I prefer at this time to take your suggestion to save time and bandwidth and wait, instead, for the results of your sea trials and racing endeavors. I enjoy the honesty you have expressed in your Harry and U articles and admire anyone who is actually building proas or, for that matter, multihulls of any kind.

Quite civil and reasonable, eh? But Denney's crap escalated and went on for years after that, of course. Still waiting...

 

 

Why can't a proa be designed to be sailed in both Atlantic and Pacific mode and the transition between the two - instead of shunting - would be this simple traditional maneuver called a tack or gybe? Why not just tack Cheers, add water ballast and sail her in "Pacific" mode on the new tack... or is the rig and board locations giving me horribly unbalance helm when I do that?

It can be done but isn't optimal for several reasons. Rigging issues, for one thing - sheeting, headstays, etc. Hulls are another; when pressed hard, the leeward hull must be capable of supporting the entire boat's displacement. The leeward pod makes less sense when it is on the windward side. Water ballast, when used, doesn't have to be dumped when shunting, as it would when tacking.

 

Russell Brown's proas work because they hit a sweet spot of balancing (so to speak) and optimizing so many factors.

 

Cheers.

Share this post


Link to post
Share on other sites

I have been sailing this since 2005. It took a few years to perfect it but with the roller furling sail it has worked very well for me.

 

33572250651_b310a5b76b_c.jpgIMG_0277 by evanbelkom, on Flickr

 

32858799004_6b7e1bfbf6_c.jpgEVB68_Full_ballast by evanbelkom, on Flickr

 

This is the tank that is installed in the ama. The ama weight is 44Lbs empty and 102 Lbs filled. With the 8' beam it works well. It takes 90 seconds to fill or drain with the electric pumps powered with the NiCD battery in the ama.

 

 

32858798934_76202ce5dd_c.jpgEVB36_Ballast_bag by evanbelkom, on Flickr

Share this post


Link to post
Share on other sites

I don't want to get into Proa's debate with Rob. I will not engage on that.

 

Lets make this simple.

 

Newick's Cheers is sailing along in Atlantic mode. Why not just tack and continue upwind in Pacific mode? The structure can obviously handle that. Its easier to support the rig. Water ballast (in the float) could add righting moment if needed. Only sheeting angles seem challenging.

 

Newick is brilliant (and I am a a hack) so if its so easy he would have done it or considered it. I am trying to understand what I am missing.

 

Its not the type of boat I want but I am curious about it as a thought experiment...

 

Wess

Share this post


Link to post
Share on other sites

I don't want to get into Proa's debate with Rob. I will not engage on that.

There is no debate. That ended many years ago. I will not engage in it either, other than an occasional reminder of how and why the acrimony developed.

 

 

Lets make this simple.

 

Newick's Cheers is sailing along in Atlantic mode. Why not just tack and continue upwind in Pacific mode? The structure can obviously handle that. Its easier to support the rig. Water ballast (in the float) could add righting moment if needed. Only sheeting angles seem challenging.

 

Newick is brilliant (and I am a a hack) so if its so easy he would have done it or considered it. I am trying to understand what I am missing.

 

Its not the type of boat I want but I am curious about it as a thought experiment...

 

Wess

 

With significant breeze and no weight in the windward ama, CHEERS would capsize. It wasn't optimized for that, though it could be sailed that way in light air.

 

Would be better for your thought experiment to start with a catamaran. Equal length hulls, displacement and 50%/50% weight distribution. Then move the mast and rig to one hull. How do you sheet the sails? What keeps the mast up? Freestanding mast with no headstays (jibs)? What are the advantages over a catamaran? What are the disadvantages if one hull is heavier?

 

When one hull weighs more than the other, the safety pod comes into play (among other issues). CHEERS had one on its windward side - installed after a capsize when it was caught aback. The Brown Pacific proa configuration addresses all these issues.

 

P.S. Pacific Proa compared to Catamaran

http://pacificproa.com/pacific_proa_compared_to_catamaran.html

Share this post


Link to post
Share on other sites

The Semans' did this in the early 60s It was the wonderful Malibu Outrigger. C.L.C. has a kit for a smaller versiom.

Share this post


Link to post
Share on other sites

Thanks Guerdon.

Proa - I would have to find drawings but if I recall from having seen it long ago, Cheers looked very much like a narrow beam catamaran with slender hulls with the rig in one of the hulls. I (maybe incorrectly) recall the hull lengths and and to a lesser extent even the underwater shape to be quite similar.

Share this post


Link to post
Share on other sites

 

Why can't a proa be designed to be sailed in both Atlantic and Pacific mode and the transition between the two - instead of shunting - would be this simple traditional maneuver called a tack or gybe? Why not just tack Cheers, add water ballast and sail her in "Pacific" mode on the new tack... or is the rig and board locations giving me horribly unbalance helm when I do that?

 

Thank you Wess for asking the tough questions, I have often wondered this myself.

Share this post


Link to post
Share on other sites

Thanks Guerdon.

 

Proa - I would have to find drawings but if I recall from having seen it long ago, Cheers looked very much like a narrow beam catamaran with slender hulls with the rig in one of the hulls. I (maybe incorrectly) recall the hull lengths and and to a lesser extent even the underwater shape to be quite similar.

 

CHEERS is well documented. The re-printed book Project Cheers is an epic treasure of proa sailing history, told with detail, yet the pace and continuity of a good bar story. Both hulls from the same mold, as I recall (not certain, the end views don't look the same), one loaded with weight and top hamper, which changes the below surface shape. Until the leeward ama is loaded up with wind pressure, doing all the lifting for righting moment!

 

cheers-plan.gif

 

Cheers2800p.JPG

 

cheers_mrb.jpg

 

Cheers053.jpg

Share this post


Link to post
Share on other sites

An Atlantic proa has, fag packet, roughly double the RM of a pacific proa, so each time you tack onto pacific, you would either have to reduce a fair amount of sail or take on around half the displacement of the boat in water ballast. Both are slow in terms of tacking and performance relative to Atlantic mode.

 

The big thing which gets overlooked with proas, particularly the pacific type, is that they can produce the maximum leeward hull length for any given displacement, which has to be the name of the game. Percentage wise, increasing length has nearly double the speed effect of reducing displacement or increasing sail area. Plus more safety, less pitching etc etc.

 

It you compared any 22 ft proa with, say an F22 trimaran, it would not be faster or have the same amount of internal usable volume. But using the same level of construction/material sophistication for the same displacement, you could build a 32 ft pacific proa which clearly has the potential to be much faster, safer and have more space inside.

Share this post


Link to post
Share on other sites

There were two or three large French proas that had equal sized below waterline hulls like Cheers but they were set up to sail in either flying (Pacific) or leeward (Atlantic) modes - so they tacked from one mode to the other. Cheers shunted, changing equal sized and shaped bow to equal size/shape stern, wind always to the windward side of the crewed hull.

I've seen a photograph of Bernard Rhodes (from Waiheke Island here in Auckland; he helped Newick build Cheers) standing beside Cheers two freshly off the mould equal sized/volume below gunwhale hulls; the windward one later had blister accommodation added..

Also, after capsizing (caught aback) during trials, Newick added a small ("horizontal hull") sponson at gunwhale height to leeward - to stop going over if caught again.

The other large French Atlantic proas like Eterna and Tahiti Douche and Lestra Sport (the latter set an Atlantic crossing record) also had equal sized hulls and sailed in Atlantic mode, crew weight and accommodation to windward, like Cheers, and they shunted.

Traditional Pacific proas in a breeze carried crew weight for stability out on the flying outrigger, heavy solid wood and not equal in volume to the main hull.

Russell Brown's Pacific proa designs, as far as I know, have slightly smaller but similar volume than main crew accommodating hull in the outrigger float, For more power in fresh conditions the Brown designs carry water ballast in the flying float.

Rob Denney's different Pacific proa, doesn't carry water ballast in his shorter and accommodation carrying windward float but it too is a flying outrigger Pacific design ... and is also similar in concept to a Flying 18 with crew out on trapeze to windward ... proven very high performance.

And this is the question that seems to be avoided by some: which is the better performance/stability solution: adding weight, water, increasing boat overall weight, lowering the sail area/power to boat weight ratio or ... maintaining original (very light) overall boat weight and maintaining stability and power through having all accommodation crew to windward in a smaller outrigger?

Agreed, trying to explain the difference between the differing proa types, is not easy.

Share this post


Link to post
Share on other sites

An Atlantic proa has, fag packet, roughly double the RM of a pacific proa, so each time you tack onto pacific, you would either have to reduce a fair amount of sail or take on around half the displacement of the boat in water ballast. Both are slow in terms of tacking and performance relative to Atlantic mode.

 

The big thing which gets overlooked with proas, particularly the pacific type, is that they can produce the maximum leeward hull length for any given displacement, which has to be the name of the game. Percentage wise, increasing length has nearly double the speed effect of reducing displacement or increasing sail area. Plus more safety, less pitching etc etc.

 

It you compared any 22 ft proa with, say an F22 trimaran, it would not be faster or have the same amount of internal usable volume. But using the same level of construction/material sophistication for the same displacement, you could build a 32 ft pacific proa which clearly has the potential to be much faster, safer and have more space inside.

 

 

^^^ This

 

When you compare proas to other multihulls, you should not compare to same length, but to same displacement. Because to a large extent, cost, accommodations, etc. is first and foremost related to displacement (for similar construction methods... of course; don't compare a pre-preg all carbon honeycomb composite to plywood + epoxy + fiber glass...)

 

And for a given displacement, for a multihull that is not foiling, like for any other "archimedian" boat, the longer the better.

Share this post


Link to post
Share on other sites

Regarding the OP question, it has been tried, with limited success shall we say...

 

Google "prao Azurex" for instance. Notice that I wrote prao, in French, not proa, in English... and the purists will tell you that it is not a prao or proa, because it does not shunt.

 

Others tried it, but I guess that instead of getting the best of both worlds, you get the worst of both worlds...

Share this post


Link to post
Share on other sites

I must be nuts to ask this here - the proa debates have always seemed odd to me - but here it goes.

 

So if I understand correctly...

 

The Atlantic proa has the weight and rig to windward and gets its stability from the buoyancy of the leeward hull. Essentially a trimaran without the windward float. Greats like Newick designed iconic boats like Cheers which are of this type.

 

The Pacific proa has the weight and rig to leeward and gets its stability from the righting moment of the windward hull (which might incorporate water ballast). Essentially a trimaran without the leeward float with a smaller windward float. Greats like Brown designed iconic boats like Jzerro which are of this type.

 

People have been fighting over the type ever since but given the greats involved on both sides perhaps we can reasonably say each has merits?

 

Then along come Rob Denny and essentially splits the middle with the Harryproa which has the weight to windward but the rig to leeward. Forgive me Rob, but please allow me without passing judgment, to ignore this type for the moment.

 

Here is what I don't understand about the Atlantic/Pacific thing...

 

A oversimplification for sure but part of the benefit of the proa is that you have greater speed potential than the tri because the weight of unused float is dispensed with along with the build time and costs for that part of the structure. But in place of simply tacking or gybing we now have this new type of a maneuver called shunting. So here is the question...

 

Why can't a proa be designed to be sailed in both Atlantic and Pacific mode and the transition between the two - instead of shunting - would be this simple traditional maneuver called a tack or gybe? Why not just tack Cheers, add water ballast and sail her in "Pacific" mode on the new tack... or is the rig and board locations giving me horribly unbalance helm when I do that?

 

Flame suit on and ready.

 

Ducking...

 

Wess

 

 

The answer to your question is that there is no reason why not, as long as the hulls are of equal weight, or could easily be made so, ideally without adding or moving any extra weight. Basically a cat with the rig on the inside of one hull (if it is stayed), which makes more sense than trying to support it in the middle of the bridge deck. Makes much more sense if it is unstayed, but that applies to all cruisers.

 

On a racing boat it doesn't make sense as the optimum weight should be biased to the windward hull.

Same applies to a performance cruiser, if the weight to be carried in the windward hull allows a smaller hull than a cat. If that hull is always to windward it sees lower stress, has less area, is easier driven, etc so can be lighter. This is demonstrated in the 50'/15m strip planked harrys which weigh 2-3 tons.

 

Shunting is not all bad. It is a little slower than tacking, and much slower than gybing (there are several ideas we are going to try to speed it up when Bucket List is ready), but set up properly, in big air and seas, shunting is easier and safer. It means that you can set enough sail for the conditions, rather than enough to get you through a tack. This makes sailing in strong winds relatively stress free. Which is why cruising types tend to love it. Shunting also allows for faster, easier to build hull shapes (no or little rocker) and fore and aft rudders, which steer better than stern hung and can replace daggerboards.

 

Re "great".

No way am I in Newick's league as a designer, or in Russ' as a builder. There are no harryproas regularly racing or crossing oceans or glamorous photos on magazine covers and the name harryproa is hard to take seriously. I have never worked with or for any famous people and my only marketing is through satisfied clients and the forums, where rabid haters follow me around trying to turn every proa thread to shit, ignoring the harrys that have been built and flinging mud at me in the hope that some will stick.

 

And yet, there are more cruising harryproas sailing and/or building than all the modern Pacific and Atlantic types combined. And most of them are for either experienced sailors who want something lighter/cheaper/easier to sail/better performing than a cat (people like you;-)), or novices who want something uncomplicated. Interesting, isn't it?

 

Rob Z,

Length is fast, but only if there is enough sail area to move it and righting moment to keep it upright. Weight and it's location is important also.

Share this post


Link to post
Share on other sites

So carrying extra water ballast in the windward float to maintain stability in fresh winds is lighter than, more stable than, faster through the water than ... no water ballast in windward (accommodation) float of a Harryproa?

You exist in a strange planet, ProAsailOr?

All this subtle balance BS is fairy tale stuff.

Where is the excess weight on a no water ballast HP design, like his latest 40 foot work?

Russell can't be happy with all this "alternative facts" nonsense from enraged and weirdo followers?.

 

 

There were two or three large French proas that had equal sized below waterline hulls like Cheers but they were set up to sail in either flying (Pacific) or leeward (Atlantic) modes - so they tacked from one mode to the other. Cheers shunted, changing equal sized and shaped bow to equal size/shape stern, wind always to the windward side of the crewed hull.

I've seen a photograph of Bernard Rhodes (from Waiheke Island here in Auckland; he helped Newick build Cheers) standing beside Cheers two freshly off the mould equal sized/volume below gunwhale hulls; the windward one later had blister accommodation added..

Also, after capsizing (caught aback) during trials, Newick added a small ("horizontal hull") sponson at gunwhale height to leeward - to stop going over if caught again.

The other large French Atlantic proas like Eterna and Tahiti Douche and Lestra Sport (the latter set an Atlantic crossing record) also had equal sized hulls and sailed in Atlantic mode, crew weight and accommodation to windward, like Cheers, and they shunted.

Traditional Pacific proas in a breeze carried crew weight for stability out on the flying outrigger, heavy solid wood and not equal in volume to the main hull.

Russell Brown's Pacific proa designs, as far as I know, have slightly smaller but similar volume than main crew accommodating hull in the outrigger float, For more power in fresh conditions the Brown designs carry water ballast in the flying float.

Rob Denney's different Pacific proa, doesn't carry water ballast in his shorter and accommodation carrying windward float but it too is a flying outrigger Pacific design ... and is also similar in concept to a Flying 18 with crew out on trapeze to windward ... proven very high performance.

And this is the question that seems to be avoided by some: which is the better performance/stability solution: adding weight, water, increasing boat overall weight, lowering the sail area/power to boat weight ratio or ... maintaining original (very light) overall boat weight and maintaining stability and power through having all accommodation crew to windward in a smaller outrigger?

Agreed, trying to explain the difference between the differing proa types, is not easy.

 

Groucho Marx, you will never understand proas or be able to explain them to anyone until you realize how important the difference is between proas designed to carry more weight on one hull or the other, leeward vs. windward. Big boats where crew weight and water ballast are small fractions of total displacement.

 

In particular, two of your statements above are demonstrably wrong and a third makes a distinction without a difference:

  • All this subtle balance BS is fairy tale stuff. [so deeply wrong!]
  • Newick added a small ("horizontal hull") sponson at gunwhale height to leeward [windward side, not leeward]
  • wind always to the windward side of the crewed hull [brilliant! but always the case, eh?]

The safety pod was added to CHEERS' windward side because the light leeward hull could be lifted too easily when caught aback. The Brown Pacific proa has a large safety pod to leeward at all times. Left alone with boom sheeted to leeward, the Pacific proa will weathercock with its pod and larger, heavy hull to leeward and small hull to windward.

 

The most subtle and difficult concept seems to be how weight distribution affects what Jim Antrim called "the footprint of stability". The idea applies to all boats but multihulls in particular, describing the relationship between COG and COB (Center of Gravity vs. Center of Buoyancy). Things get interesting from this perspective when high performance boats are pushed to their limits. Excess weight to windward makes the bow the weak leg of the footprint.

Share this post


Link to post
Share on other sites

Chillax. I thought it was just Doug Lord level that endlessly posted claims of superiority, rehashed cut and paste, all complete with colors and large font. Think the only thing missing is oddly placed caps...

 

Thanks Laurent... could not find much in English but will keep digging.

 

Thanks Rob Z... I did not initially get that but I do now. Thanks. But is it that extreme a performance hit as is suggested at same length? (I don't want to or have any intention to but...) If I dropped the windward beams and float off my F27F trimaran while sailing along (and lets assume the rig is still supported ala Cheers) I just saved about 700 lbs on a about 3000 lbs boat and have an upright Atlantic proa sailing happily along with stability provided by the buoyant leeward float. So do you think I am now faster, slower, or the same speed and point as the F27F before we ditched the windward beams and floats (on this tack)?

 

Oh and I am guessing (pretty uneducated guess) that due to my reduced RM (from lost weight to windward), the boat is fully powered up sooner and so is faster at lower wind speeds but because I can never get the RM back, its slower at higher wind speeds and about the same in the middle (I just have to reef earlier).

Share this post


Link to post
Share on other sites

Good grief. Chillax. I thought it was just Doug Lord level that endlessly posted claims of superiority, rehashed cut and paste, all complete with colors and large font. Think the only thing missing is oddly placed caps...

 

Heh, heh... Argumentum ad hominem. The blue font highlights are Groucho Marx's words, not mine. Believe him about proas and you'll be as clueless as he is.

Share this post


Link to post
Share on other sites

 

 

And yet, there are more cruising harryproas sailing and/or building than all the modern Pacific and Atlantic types combined. And most of them are for either experienced sailors who want something lighter/cheaper/easier to sail/better performing than a cat (people like you;-)), or novices who want something uncomplicated. Interesting, isn't it?

 

Rob Z,

Length is fast, but only if there is enough sail area to move it and righting moment to keep it upright. Weight and it's location is important also.

 

 

 

This is a classic example of "alternative facts". I believe that there are more John Harris designed "Madness" proas built and sailing than there are are Harry Proas (I think there are 8 sailing). I can think of at least a dozen large Pacific style proas actually sailing besides the four that I built.

Share this post


Link to post
Share on other sites

......Thanks Rob Z... I did not initially get that but I do now. Thanks. But is it that extreme a performance hit as is suggested at same length? (I don't want to or have any intention to but...) If I dropped the windward beams and float off my F27F trimaran while sailing along (and lets assume the rig is still supported ala Cheers) I just saved about 700 lbs on a about 3000 lbs boat and have an upright Atlantic proa sailing happily along with stability provided by the buoyant leeward float. So do you think I am now faster, slower, or the same speed and point as the F27F before we ditched the windward beams and floats (on this tack)?

 

Oh and I am guessing (pretty uneducated guess) that due to my reduced RM (from lost weight to windward), the boat is fully powered up sooner and so is faster at lower wind speeds but because I can never get the RM back, its slower at higher wind speeds and about the same in the middle (I just have to reef earlier).

You are guessing about right, but probably faster downwind period. But if you reinvested that 700lbs into more length and extra beam, you should be able to get a faster all round boat with less pitching etc.

Share this post


Link to post
Share on other sites

Why can't a proa be designed to be sailed in both Atlantic and Pacific mode and the transition between the two - instead of shunting - would be this simple traditional maneuver called a tack or gybe?

See http://www.tacking-outrigger.com/ for a bunch of examples, including a few larger than beach boats.

Share this post


Link to post
Share on other sites

Comparing CHEERS to JZERRO is interesting. CHEERS is a little longer (40' vs. 36') and ~1,000 lbs. lighter. JZERRO has a larger safety pod that makes a comfortable double berth. JZERRO has interior volume comfortable for two people on extended passages while CHEERS is barely adequate for one hardy soul. Would be a blast to see them race!

 

Now if JZERRO were rigged to sail well with a longer ama to leeward... would you want to? Instead of being lifted, that ama would be pressed down, taking on up to 100% displacement. ​And CHEERS needed that safety pod.

 

book_cover.jpgjzerro13-l.jpg

Share this post


Link to post
Share on other sites

Proa Sailor, you are correct to correct my statement of the sponson being to leeward, my mistake, it is to windward, normally BUT ... it is NOT to windward when the proa is caught aback, and that is my point, it is to leeward in that dangerous situation and provides buoyancy/safety while the platform heels over to what is now, to leeward. I'm meaning Cheers-Atlantic type here.That is its main purpose, stop capsize to the new leeward - aside from providing extra accommodation area In normal balanced and correct equilibrium sailing.

Notice I haven't shouted in red ink a la dOuG LOrD, just the odd capital.

Share this post


Link to post
Share on other sites

Notice I haven't shouted in red ink a la dOuG LOrD, just the odd capital.

 

I am not shouting. The statements of yours that I highlighted jump off the page at me that way.

 

Like this one, in reference to a harryproa: "it too is a flying outrigger Pacific design"

 

Really, no. It won't be flying the heavier windward hull the way a Pacific "flying proa" can be expected to do with the lighter one. There is a major asymmetry in behavior between the two models. It's at the heart of the dispute. As he did on MOXIE, Dick Newick probably designed the ama on CHEERS to be 100% displacement and no more, so the boat can tell the skipper when to back off, when that leeward ama deck is awash. Sure, a 200% or more ama can be used to fly a heavier hull to windward. But then all the comments about a heavy water ballasted ama slamming into the water on a Pacific proa must be applied to the harryproa main hull, and it will be ~3 times heavier than the Pacific proa's windward ama!

Share this post


Link to post
Share on other sites

Three times heavier; not so sure about that. Heavier, yes but the Harryproa windward "pod" is very minimal and the "outrigger" is going to be light, even carrying one or two crew. Need to ask Rob about this. And referring to traditional Micronesian Pacific proas, their solid outrigger was chosen from heavy timber, it was not light buoyant wood and would also have waterlogged over time too..So, in my view, no red ink, the 40 foot racing Harryproa is very much a flying Pacific design. And very much the same concept (admittedly more conservative) as the original world speed record holding, MacAlpine-Downie proa Crossbow of the 1970s.

Share this post


Link to post
Share on other sites

Proa Sailor, you are correct to correct my statement of the sponson being to leeward, my mistake, it is to windward, normally BUT ... it is NOT to windward when the proa is caught aback, and that is my point, it is to leeward in that dangerous situation and provides buoyancy/safety while the platform heels over to what is now, to leeward. I'm meaning Cheers-Atlantic type here.That is its main purpose, stop capsize to the new leeward - aside from providing extra accommodation area In normal balanced and correct equilibrium sailing.

Notice I haven't shouted in red ink a la dOuG LOrD, just the odd capital.

 

Whats the matter-"Frog" caught in your throat?!

Share this post


Link to post
Share on other sites

Good humour, DoUg, well done. Cheers.

Share this post


Link to post
Share on other sites

 

 

Why can't a proa be designed to be sailed in both Atlantic and Pacific mode and the transition between the two - instead of shunting - would be this simple traditional maneuver called a tack or gybe? Why not just tack Cheers, add water ballast and sail her in "Pacific" mode on the new tack... or is the rig and board locations giving me horribly unbalance helm when I do that?

 

Thank you Wess for asking the tough questions, I have often wondered this myself.

 

Still wondering if it was a wise decision. Lets see if we come out the other side alive and with a better understanding. Sounds a bit like the R2AK, LOL.

 

 

......Thanks Rob Z... I did not initially get that but I do now. Thanks. But is it that extreme a performance hit as is suggested at same length? (I don't want to or have any intention to but...) If I dropped the windward beams and float off my F27F trimaran while sailing along (and lets assume the rig is still supported ala Cheers) I just saved about 700 lbs on a about 3000 lbs boat and have an upright Atlantic proa sailing happily along with stability provided by the buoyant leeward float. So do you think I am now faster, slower, or the same speed and point as the F27F before we ditched the windward beams and floats (on this tack)?

 

Oh and I am guessing (pretty uneducated guess) that due to my reduced RM (from lost weight to windward), the boat is fully powered up sooner and so is faster at lower wind speeds but because I can never get the RM back, its slower at higher wind speeds and about the same in the middle (I just have to reef earlier).

You are guessing about right, but probably faster downwind period. But if you reinvested that 700lbs into more length and extra beam, you should be able to get a faster all round boat with less pitching etc.

 

 

Yes, Rob Z, understood and agreed. These are the benefits I see to the Atlantic proa approach. But then because I am an old dog unwilling to learn new tricks ( ;) ) I can't shunt and instead tack and end with with a Pacific proa so now I need to understand that beast...

 

Russell/Joe - Help me better understand the Pacific proa. Specifically, where/how does it get its RM given the typically small windward float? Or say on Jezerro what % of the total available RM comes from the unballasted windward float (I am guessing its a very low % of total RM when the boat is water ballasted). So is the RM mostly all moveable ballast be it crew weight or water?

Share this post


Link to post
Share on other sites

Yes, Rob Z, understood and agreed. These are the benefits I see to the Atlantic proa approach. But then because I am an old dog unwilling to learn new tricks ( ;) ) I can't shunt and instead tack and end with with a Pacific proa so now I need to understand that beast...

 

Don't forget what Rob Zabukovec wrote so well about Pacific proas earlier:

 

The big thing which gets overlooked with proas, particularly the pacific type, is that they can produce the maximum leeward hull length for any given displacement, which has to be the name of the game. Percentage wise, increasing length has nearly double the speed effect of reducing displacement or increasing sail area. Plus more safety, less pitching etc etc.

 

It you compared any 22 ft proa with, say an F22 trimaran, it would not be faster or have the same amount of internal usable volume. But using the same level of construction/material sophistication for the same displacement, you could build a 32 ft pacific proa which clearly has the potential to be much faster, safer and have more space inside.

 

Russell/Joe - Help me better understand the Pacific proa. Specifically, where/how does it get its RM given the typically small windward float? Or say on Jezerro what % of the total available RM comes from the unballasted windward float (I am guessing its a very low % of total RM when the boat is water ballasted). So is the RM mostly all moveable ballast be it crew weight or water?

 

The rule of thumb I've used for decades, since observing the displacement of Kauri's ama, is ~25% total displacement at rest on a Pacific proa's windward ama, 75% on the main/leeward hull, increasing to 100% as the ama flys. Most of that is static, unmoveable stuff like the interior, the mast, cockpit and engine. Adding 400 lbs. of water ballast on a ~4000 lb. boat is significant - 10% of total. Ratio changes to 32% of total weight in the ama, moving the CG outboard and keeping it low. Like two big guys on the windward hull 24/7 who don't eat and you can drop off any time. RM is a standard measurement of CG related to CB. No secrets, no magic.

 

Keep in mind that flying the ama is easily prevented. Like the warning when a leeward ama's deck is awash, almost flying is often ideal.

 

jzerro_lat38.jpg

Share this post


Link to post
Share on other sites

 

 

 

Why can't a proa be designed to be sailed in both Atlantic and Pacific mode and the transition between the two - instead of shunting - would be this simple traditional maneuver called a tack or gybe? Why not just tack Cheers, add water ballast and sail her in "Pacific" mode on the new tack... or is the rig and board locations giving me horribly unbalance helm when I do that?

 

Thank you Wess for asking the tough questions, I have often wondered this myself.

 

Still wondering if it was a wise decision. Lets see if we come out the other side alive and with a better understanding. Sounds a bit like the R2AK, LOL.

 

 

......Thanks Rob Z... I did not initially get that but I do now. Thanks. But is it that extreme a performance hit as is suggested at same length? (I don't want to or have any intention to but...) If I dropped the windward beams and float off my F27F trimaran while sailing along (and lets assume the rig is still supported ala Cheers) I just saved about 700 lbs on a about 3000 lbs boat and have an upright Atlantic proa sailing happily along with stability provided by the buoyant leeward float. So do you think I am now faster, slower, or the same speed and point as the F27F before we ditched the windward beams and floats (on this tack)?

 

Oh and I am guessing (pretty uneducated guess) that due to my reduced RM (from lost weight to windward), the boat is fully powered up sooner and so is faster at lower wind speeds but because I can never get the RM back, its slower at higher wind speeds and about the same in the middle (I just have to reef earlier).

You are guessing about right, but probably faster downwind period. But if you reinvested that 700lbs into more length and extra beam, you should be able to get a faster all round boat with less pitching etc.

 

 

Yes, Rob Z, understood and agreed. These are the benefits I see to the Atlantic proa approach. But then because I am an old dog unwilling to learn new tricks ( ;) ) I can't shunt and instead tack and end with with a Pacific proa so now I need to understand that beast...

 

Russell/Joe - Help me better understand the Pacific proa. Specifically, where/how does it get its RM given the typically small windward float? Or say on Jezerro what % of the total available RM comes from the unballasted windward float (I am guessing its a very low % of total RM when the boat is water ballasted). So is the RM mostly all moveable ballast be it crew weight or water?

 

 

It's not a "very low % of overall RM" on Jzerro. There has been a lot of misinformation in these threads about how Brown style proas have little or no righting moment. Ignore that info. I have attached a load cell to the ama of Jzerro and lifted it 1mm clear of the water, and the scale read 825 lbs. That's a lot of righting arm well to windward. Compare it to a mini transat design, which has far less RM and slightly less sail area than Jzerro, and you can see she's pretty well ballasted without water already. Now, if I add ballast unnecessarily, even as little as 10 gallons, Jzerro will sail in a jerky, unbalanced manner, because the short hull is constantly losing an Archimedean battle to the much longer main hull. Adding weight to the shorter hull exacerbates that struggle. This is one reason I am lengthening Jzerro's ama this summer. It's also the reason I dump ballast as soon as the wind softens. So, IMO, if the ama is a lot shorter in relation to the main hull, the jerky acceleration/deceleration if the windward hull will be amplified with max RM in every condition, especially in waves. For me, it would be like sailing an A Cat, with a 9' windward hull and the skipper fully trapped out in every condition and wind angle. It might be faster sometimes, but the sailors that are moving their weight around are going to be faster over the long haul, and when their full length windward hull does touch the water, their boats will decelerate less than then hypothetical ACat. Balance is not a myth.

 

To be clear, most of what I'm saying is based on observations made while sailing Jzerro over 7,000 miles during the last 1.5 years. I've experimented with a lot of ballast and weight placement combinations, and this is what I've seen.

Share this post


Link to post
Share on other sites

Comparing CHEERS to JZERRO is interesting. CHEERS is a little longer (40' vs. 36') and ~1,000 lbs. lighter. JZERRO has a larger safety pod that makes a comfortable double berth. JZERRO has interior volume comfortable for two people on extended passages while CHEERS is barely adequate for one hardy soul. Would be a blast to see them race!

 

 

Last I heard, Cheers had been restored and was sailing in France, and Sven had a Russell Brown proa in the region, I forget which.

 

As he did on MOXIE, Dick Newick probably designed the ama on CHEERS to be 100% displacement and no more, so the boat can tell the skipper when to back off, when that leeward ama deck is awash. Sure, a 200% or more ama can be used to fly a heavier hull to windward. But then all the comments about a heavy water ballasted ama slamming into the water on a Pacific proa must be applied to the harryproa main hull, and it will be ~3 times heavier than the Pacific proa's windward ama!

 

Look at the line drawing of Cheers that you posted. The waterline is drawn for the two hulls, identical below the sheer line, having the same draft, thus each carrying half the weight. A 100% displacement hull should, in that situation, have as much volume above as below the waterline. Looking at the central station of the lee hull, you can see about twice as much cross sectional area above as below the waterline. If all sections had the same ratio, that would indicate a minimal volume of 150% of total displacement. The lines of the weather hull indicate that between rocker and sheer, the ratio of cross sectional area above and below the waterline becomes more extreme towards the end of the boat. I am guessing a volume of at least 200% of total displacement.

 

That makes sense on two counts: one, the centre of buoyancy of a trimarans floats can be as far ahead of the centre of gravity as the designer wishes, meaning the boat remains level or pitches up as it heels. The proa's fore and aft symmetry rules out that option. A 100% volume lee hull on a proa would warn you that you are pressing too hard not by the deck being awash, but, thanks to sail pressure, by sticking its nose in. That might be unpleasant. Two, the higher volume lee hull makes it less likely the boat trips over that hull when lying ahull, which was Cheers' storm tactic, if I remember correctly.

 

As for slamming, things might be a little more complicated than that. Vertical acceleration should depend first on how much of a run-up the weather hull had before it hits the water again, i.e. how far it lifted. Lighter load should mean easier lifting.

 

Second, vertical acceleration should depend on waterline loading, on how quickly the waterline gains area with immersion, and on how flat the bottom is. Waterline loading depends on the load on the hull and waterplane area. The Harryproa carries a higher load, but the Pacific proa tends to have a smaller waterline area, so it is not clear which design has the advantage. Either way, greater load should go with less vertical acceleration, which also means the hull goes deeper.

 

Of course, a windward hull immersing itself deeper in a wave could also pull the boat off course. How much that matters should depend, apart from hull shape, on how much cross sectional area the hull gains as it is immersed. The Harryproa carries a lot of windward volume to provide accommodation space, but also more weight to windward which can provide momentum to push the windward hull trough the wave. The Pacific goes the other way on both. Again, it not clear that either design has an inherent advantage.

 

And in case someone cares, that expectation is based entirely on theory, not on practical experience, and I may have overlooked something that makes real boats behave differently.

 

Both vertical accelerations and yaw should be worse the lower the density of the windward hull is. The Harryproa windward hull can't help having a lot of volume for its weight, because that is where people need to fit in. The Pacific proa does offer a choice. I have long wondered why Russell's boats have amas with so much more volume for their weight than traditional Pacific proas. I guess it is a deliberate trade-off, accepting greater vertical accelerations in exchange for greater safety when caught aback. Russell, would you be willing to comment?

 

Edit: and I just see r.finn describing a reality in conflict with my expectation. Is the jerky acceleration you mention vertical, translating into roll, or does it pull the boat off course?

Share this post


Link to post
Share on other sites

Pulls boat off course. Requires more helm movement. Wears down autopilot :)

Share this post


Link to post
Share on other sites

Thanks for the info ryan, so much to learn about this boat.

sven stevens has designed turbo rigs for pacific proas but thats all theory, you are the only one doing it at the moment.

thanks for keeping us enthausiast updated on facebook!

 

fingers crossed paul bieker or sven stevens ever builds a racing proa.

Share this post


Link to post
Share on other sites

Pulls boat off course. Requires more helm movement. Wears down autopilot :)

So momentum doesn't compensate for the added drag of immersion as much as I thought. Useful to know. Thanks.

 

Would you expect the drag of the ama in a seaway, and thus yaw, to be reduced if the ama could pitch independently, as on some designs?

 

Thinking a bit more, do you expect this attention to the correct balance of weight would be needed if a design went radically the other way, with an ama with barely enough volume to support its weight at rest? It should gain very little drag when going through a wave instead of over.

 

Or, of course, a hinged vector foil could let you safely fly the ama, so long as the foil doesn't lose its grip. Or Rob Zabukovec's windward lifting Bruce foil could let you fly the ama through a wider range of heeling moments, without slamming it into a wave, and if the foil lost lift, the boat would only settle and possibly luff from the windward drag, but it should not capsize.

Share this post


Link to post
Share on other sites

Rob Z - Thanks for the link. Its going to take me a while to get through and understand that. But I think (?) I see the doubling of RM using water ballast, suggesting to me (perhaps incorrectly) that is a critical and necessary aspect of larger voyaging Pacific (flying) proas. Joe's pic suggests same. Cant imagine how that boat would stay upright in those conditions unless the windward float was heavily (water) ballasted.

 

Ryan - Thanks tons for sharing your thoughts. Even if I don't want a proa the concepts here are really interesting to me as a sailor and especially as a multihull sailor. Very interesting that you are thinking of lengthening the windward hull on Jezerro, an Atlantic proa. That takes me back to...

 

Lets return to the simple thought experiment that seems easy to follow and understand.

 

I have a Corsair F27F trimaran. Its a ~3000 lbs boat with ~700 lbs in each set of beams and floats. These are not high buoyancy floats by today's standards. Its not designed to sail with the main hull flying which is maybe important for this little thought experiment. (I don't plan or want to) but if I was sailing along I could drop the windward floats and beams and reduce boat weight by more than 25% and have an Atlantic proa. The structure would be fine, the sheeting angles fine, and with a small bit of work the rig could be supported. Per the back and forth w Rob Z I think most agree that so long as I stay on this (Atlantic proa) tack the boat will be faster upwind and down, more powered up in lighter air and needing to be reefed sooner in breeze. But a fine boat and better than the original. And it could be faster yet if we used some of the dropped weight to extend LWL. But lets ignore that and just leave F27F's windward floats and beams that I dropped off, behind.

 

But now lets tack or gybe this imaginary F27F (sans windward beams and floats) Atlantic proa so she become a Pacific proa (now having windward but sans leeward beams and float). While she was sailing along fine in Atlantis proa mode a moment ago, I expect she (this exact same boat) capsizes in a heart beat due to lack of adequate RM when I tack into Pacific proa mode. I expect I need to add significant water ballast to the (now) windward float. No intent to impune or imply anything re which is the better of the two types... just wanting to understand...

 

* So do I have this right?

 

Now here comes the tricky part... if we took my F27F and dropped beams and floats and sailed it in Atlantic mode we are faster than the F27F began. But I'm not sure if I do same and sail it in Pacific mode. I think I maybe have to add so much water ballast I am slower.

 

* Am I correct that I need water ballast or if not where does the (adequate) RM come from in this example of the F27F in Pacific proa mode?

 

* Using the F27F example am I faster or slower than the tri when I drop the beams and float and sail in Pacific proa mode (fine to assume use of water ballast)?

Share this post


Link to post
Share on other sites

Day sailing with four or more people aboard, moving people may be easier than using water ballast. If you have cargo lashed on deck, less water ballast. Often none, just by using less sail or driving and trimming to ease off. Love this one! Smooth, fast sailing.

Share this post


Link to post
Share on other sites

I could drop the windward floats and beams and reduce boat weight by more than 25% and have an Atlantic proa.

 

There is much more to it than what your hypothetical considers. Redistributing weight? Shunting instead of tacking, or both? Atlantic and Pacific proas both need that safety pod; the Pacific proa keeps it to leeward, like a safety ama on Hawaiian canoes. On a Pacific proa, balance is found on one hull, just barely loading (dragging, flying) the windward ama. Atlantic and harry proas "balance" by shifting weight more equally between two hulls.

Share this post


Link to post
Share on other sites

Proa - Lets just keep it simple for the moment. I get its not ideal but I think there is agreement that we dropped the windward beams and float off that trimaran and do nothing more, so long as it just continued on that tack (in Atlantic proa mode), its a faster better boat than the original boat (tri). Its intuitive and easy to understand how an Atlantic proa works well and can be a better boat than the tri. You keep preaching the Pacific proa is better yet. OK but if I take my tri and had dropped the leeward beams and float off (instead of the windward ones) - and do nothing else... we flip. Gotta add water ballast in the pacific proa mode for stability.

 

* Having done so is it faster or slower than the tri it came from?

Share this post


Link to post
Share on other sites

 

Pulls boat off course. Requires more helm movement. Wears down autopilot :)

So momentum doesn't compensate for the added drag of immersion as much as I thought. Useful to know. Thanks.

 

Would you expect the drag of the ama in a seaway, and thus yaw, to be reduced if the ama could pitch independently, as on some designs?

 

Thinking a bit more, do you expect this attention to the correct balance of weight would be needed if a design went radically the other way, with an ama with barely enough volume to support its weight at rest? It should gain very little drag when going through a wave instead of over.

 

Or, of course, a hinged vector foil could let you safely fly the ama, so long as the foil doesn't lose its grip. Or Rob Zabukovec's windward lifting Bruce foil could let you fly the ama through a wider range of heeling moments, without slamming it into a wave, and if the foil lost lift, the boat would only settle and possibly luff from the windward drag, but it should not capsize.

 

 

I bought a Slatts22 in 1988 and it does what you describe quite well!

 

http://www.signaldesign.net/slattsreview.html

Share this post


Link to post
Share on other sites

Proa - Lets just keep it simple for the moment. I get its not ideal but I think there is agreement that we dropped the windward beams and float off that trimaran and do nothing more, so long as it just continued on that tack (in Atlantic proa mode), its a faster better boat than the original boat (tri). It just can't change tack because if we tack it - or had dropped the leeward beams and float off (instead of the windward ones) - and do nothing else... we flip. Gotta add water ballast in the pacific proa mode for stability.

 

* Having done so is it faster or slower than the tri it came from?

Oversimplification won't explain a Pacific proa. Your assumption to "do nothing more" after lopping off the windward ama on a trimaran ignores the deliberate arrangement of static weight I mentioned to have ~25% of total displacement resting on the windward ama, before any water ballast or crew rail meat effects.

Share this post


Link to post
Share on other sites

 

Proa - Lets just keep it simple for the moment. I get its not ideal but I think there is agreement that we dropped the windward beams and float off that trimaran and do nothing more, so long as it just continued on that tack (in Atlantic proa mode), its a faster better boat than the original boat (tri). It just can't change tack because if we tack it - or had dropped the leeward beams and float off (instead of the windward ones) - and do nothing else... we flip. Gotta add water ballast in the pacific proa mode for stability.

 

* Having done so is it faster or slower than the tri it came from?

Oversimplification won't explain a Pacific proa. Your assumption to "do nothing more" after lopping off the windward ama on a trimaran ignores the deliberate arrangement of static weight I mentioned to have ~25% of total displacement resting on the windward ama, before any water ballast or crew rail meat effects.

 

 

 

If you dropped the leeward float and beams off an F27 I don't think you would have more than "~25% of total displacement resting on the windward ama, before any water ballast or crew rail meat effects." Might actually be pretty darn close to that as luck would have it. So I think it meets your test.

Share this post


Link to post
Share on other sites

 

 

If you dropped the leeward float and beams off an F27 I don't think you would have more than "~25% of total displacement resting on the windward ama, before any water ballast or crew rail meat effects." Might actually be pretty darn close to that as luck would have it. So I think it meets your test.

 

For that to be true, 50% of the weight of a complete F27 would have to be in beams and amas. With the main hull being larger, containing accommodation, rig, engine, ground tackle and payload, that seems unlikely. Your thought experiment should include shifting some of that weight.

Share this post


Link to post
Share on other sites

Thought experiments, imaginary boats, all the same thing.

Share this post


Link to post
Share on other sites

 

 

 

If you dropped the leeward float and beams off an F27 I don't think you would have more than "~25% of total displacement resting on the windward ama, before any water ballast or crew rail meat effects." Might actually be pretty darn close to that as luck would have it. So I think it meets your test.

 

For that to be true, 50% of the weight of a complete F27 would have to be in beams and amas. With the main hull being larger, containing accommodation, rig, engine, ground tackle and payload, that seems unlikely. Your thought experiment should include shifting some of that weight.

 

Would need Ian to confirm and don't think its exactly half half but again, its about a 3000lb boat and I recall a set of beams and float being near 700lb (both sides about 1300). Welcome correction if that is wrong.

 

Joe - don't know why you get so pissy about this stuff. I'm honestly curious and have no vested interest. But telling folks its better because you say so like its some religion... well maybe that what Pacific proas are but I doubt it. At least you can look at a tri and understand how and why it works and is fast and safe. Same is true for the Atlantic proa.

 

Nevermind. The proa topic always get ugly and I have no interest in that.

Share this post


Link to post
Share on other sites

 

 

All I know is that whenever I've seen videos of Russ' boat sailing fast like that...

 

I think:

1) Oh how I would LOVE to sail that fast and smoothly! It takes my breath away and is sensual to boot!

2) Can't I do that but not have to drop the jib, shift rudders and expend so much effort just to tack?

3) I've often thought of what Wess is asking about, a tacking outrigger seems to be a compromise that could work

4) Proas seem to be mostly just long, light weight boats with an optimum SA/D ratio and long LWL relative to weight. I don't need the 'ultimate', technically fastest, solution, just one that is noticeably BETTER than most of what folks sail today. ( I note that Russ' new boat the G-32 seems to share most of these characteristics as well and also looks like VERY fun sailing, so I suspect these are the keys to fast sailing.)

5) I'll take the extra length of a boat and subsequently, relatively minimal accommodations to get this kind of sailing...

Share this post


Link to post
Share on other sites

 

Would need Ian to confirm and don't think its exactly half half but again, its about a 3000lb boat and I recall a set of beams and float being near 700lb (both sides about 1300). Welcome correction if that is wrong.

 

 

OK, but is that 3000lb for an empty boat? Say it is and you add three crew. Then beams and ama end up being 20% of the weight. How much of that is beams and how much ama? So say the ama weighs 12% of the original F27 + crew weight, and the beams 8%. But we lost 20% of the original weight, so the ama now weighs 15% of the updated weight, and the beams 10%. In your scenario, the ama carries its own weight, and roughly half the weight of the beams, the other half being carried by the main hull. So the resting load on the ama should be 20% of the reduced weight of the tacking outrigger in racing trim. A lot closer to what you proposed than I thought.

 

I thought Inigo Wijnen had commented on how his tacking outrigger Gaia 2 behaved on Atlantic and Pacific tacks, but I can't find the text. Does anyone else remember this?

Share this post


Link to post
Share on other sites

Here's a different viewpoint- I put together a windsurfer proa that was as close as I could get to a traditional micronesian model lagoon

Racer, which was basically this:

 

(Edit: sorry I can't draw it on this board- but basically a long round skinny hull, a 6' beam, and a short skinny hull)

 

This was before design software, so main hull was ~ 1' beam, 16' long, float was 3" beam and 3' long. Longitudinal symmetry for both.I used an old carbon windsurfing mast for the beam, and a 7M*2 D2 sail. No pics. ~1983.

 

Anyhoo, what surprised me was when I sailed the thing in pacific mode was the float would make enough drag so I had to move the CE of the rig forward enough so my back was in danger. If I tried to step forward to make things easier on my body, the bow went down, hunted, and instantly I was rounding up. I couldn't get enough speed to vang up the foil, which was my initial design hope, so the float would be flying a bit, and everything happened fast enough so I never could just sit down on the beam and not go swimming. So one day I was pulling up the sail out of the water, and the sail got a little out of control, and the boat rotated around so the float was to leeward. I was wet and tired, so I thought 'what the fuck' and tried it. The float pulled the bow to leeward, and without stepping too far

Aft, I could balance things out, and it was easier to control the stern sinking and the resulting falling off using my foot pressure...

 

So the Atlantic configuration meant the CE of the sail could be farther back, which was nice, and easier on my body. The problem was that when I dropped the rig, nothing good happened- either the rig landed on top of the float and stayed there, so if I fell in the water, the thing would sail off slowly, or if the rig fell up by the bow to leeward, the float would run over, under, in to it, which was a pain, esp. when the universal popped out off the hull. But I shunted a few times with the float to leeward. It was less anxiety inducing to fall to windward not having to miss the float or beam. If the float had planed easily, I would have pursued the thing, but I liked sailing my D2 better, so onto the bonfire of that vanity, to coin a phrase ;)

 

I understood through this why the Atlantic configuration might be a bit more convenient for sail deployment. I was lucky enough to talk to Mr. Newick just before he died (about a design I was lusting to have built (and plywood sails!)), and he confirmed the float drag, was delighted I tried a windsurfer proa, but frankly thought I was a bit nuts.

 

So the drag from the float is real. I think Mr Smith had the right idea with a floaty hydrofoil, which might work either way. DSS might work to leeward with a Mr Smith foil to windward.

 

But is that a proa? :)

 

Hails of derisive laughter!

Share this post


Link to post
Share on other sites

It s all very fascinating.

I've always thought that if I went completely bonkers and began pissing around with proas I'd attempt something similar to my trifoilers - and that is, a leeward or a flying proa concept with small ama and then place a foil there similar to what I have on Sid (see photograph).

Now, ignoring the screams of outrage emanating from the odd humourless proa purist crank here, just pause a second. On my foilers with small floats, the foil to leeward with attack angle of 2-3 degrees (so in hypothetical craft the windward beam is chopped, making it Atlantic Cheers proa-type), I have never had helming problems, the boat runs straight, strong gusts have no effect, the foil just works harder and lifts float as you accelerate. I need to add that on Sid the windward float and foil fly clear of water surface, no drag.

So to make a leeward proa like so would be simple. Need I add that the overall platform would be very light, which equals plus fast, and easy steering. Foils at speed lock into the water, pitching problems almost disappear.

Now you could do the same thing to create a flying proa - except you would need to be able to adjust the angle of attack of the now windward float foil, meaning negative attack in strong winds to hold windward float/foil down - and alternatively in lighter airs change attack to positive. The Atlantic type would be easy to create, not quite so with the Pacific flyer.

Of course the main hull in either type would require double ends and so on, plus a central (wing?) mast and other complications. Cheers.

post-100779-0-88626000-1490911075_thumb.jpg

Share this post


Link to post
Share on other sites

Ogives sing like the furies at this point. So Mr. Marx, Sir, while I tie myself to the mast, I've wondered for a long time if, on a real size craft (like Sid, for example) it would be easier to swing the beam the hydrofoil is fixed to to balance the helm, rather than all the machinations (and duplications) to move the sails. Move the CLR rather than the CE, in NA land. Put an arm on the beam to keep the hydrofoil parallel to the hull.

 

As far as the adjustable AoA foil, that's been done. The guy used to sell 'me down the hill from us. Manual control of foil lift. And I hope he'll forgive me but I cant remember his name. His approach was a Malibu tacking outrigger appraoch, and helm balance seemed fine without moving the CE or the CLR when the hydrofoil was flying the float on either tack, pulling up or pulling down. So the only adjustment would be the AoA of the foil. Jeez, on a 30er, you could sit in the outrigger float with the foil right underneath, flying over the ocean, SailRocket Style, with a very short control linkage from your hand to the foil. That would be a rush, and not very complex. Crashing would be, um, a good story, esp. if you lost grip in Pacific mode. You could ride on top of the float, exposed, Mad Max Bad Guy style, white knuckling a joystick while strapped to an alloy seat! Holy shit! Goggles and athletic cup required!

 

You might even do it with a shunting proa, ogive main, helm swiveling 180 each shunt. The tacking outrigger seems easier, and its been done...

Share this post


Link to post
Share on other sites

Wess,

 

FWIW, Below is a selection from my data base with Corsair F27 and a few similar tri's added. They all have 300kg added so they are more or less sailing weights.

 

I have tried to be accurate, but am reliant upon multiple sources all telling the truth. Base (or average) Speed is a fag packet way of comparing the effect of the 3 main variables and their interaction.

 

Draw your own conclusions.

 

Remember also that there are a number performance things you can do with proas, that you can't with other multihulls and foils are particularly interesting. Not necessarily full lift off either.

 

The real tragedy with proas is that there have never been enough in one place to compare and evaluate in any sensible fashion. The unpleasant abuse and argument between the factional disciples does not help cause of the Proa religion either. There is room for all types of proas, just as they were throughout the Paciific for hundreds of years, and well designed enough, they should all be as fast if not faster and definitely cheaper than any comparable multihull. Unless you are into short tacking duels.post-118275-0-90559800-1490914559_thumb.jpeg

Share this post


Link to post
Share on other sites

Yet again another hopeless case loony? Talking to you Amati.

But lots of insane merit in what you're saying.

Yes, you could swing the beam a la Scizzors but I sense too many types of disasters. Does Randy actually swing his beams while sailing? I think altering foil angles on the Pacific type would be the easier, safer solution.

Share this post


Link to post
Share on other sites

Yet again another hopeless case loony? Talking to you Amati.

But lots of insane merit in what you're saying.

Yes, you could swing the beam a la Scizzors but I sense too many types of disasters. Does Randy actually swing his beams while sailing? I think altering foil angles on the Pacific type would be the easier, safer solution.

IIRR, it broke while sailing. But if you think about it, one of the things it does is move the lee hull forward, which kind of implies that the thing scizzors on every tack.

 

Frankly though, I'm going to have a beer and doodle the mad max thing. Footpeddle steering, main only, mainsheet out to the float.

 

Christ! A tacking Crossbow (II?) with a foil!!!! Yikes!

Share this post


Link to post
Share on other sites

Yet again another hopeless case loony? Talking to you Amati.

But lots of insane merit in what you're saying.

Yes, you could swing the beam a la Scizzors but I sense too many types of disasters. Does Randy actually swing his beams while sailing? I think altering foil angles on the Pacific type would be the easier, safer solution.

You talkin' to me? Huh??? :)

 

When I get the odd thingie I'm slaving away at out in the garage done, and if it works, I'll post a pic. But it's not an IC no float proa-ish swiveling seat dipping lug thingie this time. No Sir. No Sir.

Share this post


Link to post
Share on other sites

Wess,

 

FWIW, Below is a selection from my data base with Corsair F27 and a few similar tri's added. They all have 300kg added so they are more or less sailing weights.

 

I have tried to be accurate, but am reliant upon multiple sources all telling the truth. Base (or average) Speed is a fag packet way of comparing the effect of the 3 main variables and their interaction.

 

Draw your own conclusions.

 

Remember also that there are a number performance things you can do with proas, that you can't with other multihulls and foils are particularly interesting. Not necessarily full lift off either.

 

The real tragedy with proas is that there have never been enough in one place to compare and evaluate in any sensible fashion. The unpleasant abuse and argument between the factional disciples does not help cause of the Proa religion either. There is room for all types of proas, just as they were throughout the Paciific for hundreds of years, and well designed enough, they should all be as fast if not faster and definitely cheaper than any comparable multihull. Unless you are into short tacking duels.attachicon.gifimage.jpeg

 

Rob Z - Thanks. Its going to take me a while to dig through all that and try to make heads or tails. Need somebody smarter than me! We are looking at some catamaran platform to refit to our cruising cat vision and working with an NA who is also a friend. I will have to point him to this thread and no doubt it will become a topic of conversation and a good excuse to have another beer. Don't want to build a purchase a proa but its an interesting topic (when folks stop shouting at each other, LOL)!

 

Also hoping Ryan Finn drops back in. An unbiased sort who has practical experience with the pacific type I think. Really curious how he could single hand that and push it under autopilot. Once the flying pacific proa starts flying / skimming (speed wise and its windward hull) its at the point of diminishing stability, no? Just seems like it would have to be sailed very conservatively but others would know better than I.

Share this post


Link to post
Share on other sites

Wess,

 

You also need to look up Russ Brown's own thoughts and discussions on proas. Easy enough to find if you are really interested. Also the Sven Stevens link I gave you. Both of these guys have sailed thousands of miles on pacific proas, often with wives and families aboard and rarely lifted (or needed to lift) an ama and did not feel hopelessly over or under powered. Sven actually shortened his cross beams because he reckoned that he had too much RM.

 

You lose a lot if you make a Proa a tacking one. Better to decide which one sided Proa faction you can believe in most and work at getting the most out of that particular direction.

 

And hopefully, one day we will cross tacks/shunts with each other and compare notes.

 

Rob.

Share this post


Link to post
Share on other sites

I dunno guys. We start with "I want longer, cheaper"

 

So we have a proa, with mast in the main hull to lower loads compared to a beam, but it kinda takes up space and there's the whole shunting thing

 

So we try the tacking proa, not much different structure wise but we lose some weight savings, and to address the space issue maybe move the accommodations to the beam

 

Darn it, still have some control issues with the short ama being all draggy, let's make it longer. Well, now we have accommodations centrally, which means we have a place for a mast, and if we deck mount we can have low stress rigging with a wide base.

 

 

Don't we end up with a Gougeon 32?

Share this post


Link to post
Share on other sites

 

Still wondering if it was a wise decision. Lets see if we come out the other side alive and with a better understanding. Sounds a bit like

 

Proas- Applying a Blow Torch

 

 

 

FIFY

Share this post


Link to post
Share on other sites

Not crossbow II! Crossbow I! See the helm sitting in the float?_post-906-0-07095200-1490937656.jpg

Share this post


Link to post
Share on other sites

Sorry for being pedantic Amati but that is the original Crossbow. Crossbow 2 was a swiveled catamaran with two masts, one on each hull.

I'm sure the angled forward leeward hull design influenced Randy Smythe with Sizzors because C2 held world speed record for many years.

Another interesting aspect of the original flying proa Crossbow is that later a lifting foil was added to the the outrigger (below where the helm was perched in his cockpit hole) to soften the transition from flying to touchdown.

Share this post


Link to post
Share on other sites

The

Sorry for being pedantic Amati but that is the original Crossbow. Crossbow 2 was a swiveled catamaran with two masts, one on each hull.

I'm sure the angled forward leeward hull design influenced Randy Smythe with Sizzors because C2 held world speed record for many years.

Another interesting aspect of the original flying proa Crossbow is that later a lifting foil was added to the the outrigger (below where the helm was perched in his cockpit hole) to soften the transition from flying to touchdown.

I was a music perfesser for a time, so a pedantic were I, for a time. Thanks for the warning though- always appreciated, and softens the blow.

 

The foil flitted through my brain, but Morpheus was beckoning, and I concluded I was projecting. <sigh>

 

Hadn't made the Edward Scizzorshandlink between McAlpine- Downey and Smythe. Cool. They do both have very upper class English sounding (and spelled) names, no?

 

The AYRS crowd being who they were, you don't suppose McAlpine-Downey entertained the idea of a foil pulling the float down? (That is flitting through my brain now.) Given the tech of the day it probably would have broken the boat. ( I may have read that somewhere) But it might have nixed the sprinting beam meat. Less moving windage. :) Was the foil under the float diamond shaped? Seem to remember that....

 

It's 4 am. Back to sleep.

Share this post


Link to post
Share on other sites
Interesting times! Especially to those who have been discussing proas for any length of time. Joe/proasailor admits that RM is necessary, Ryan makes Jzerro's windward hull bigger as it slams when it is ballasted and floating and near consensus (apart from Joe) that the windward hull is usually in the water on weight to leeward proas.
I look forward to seeing where the rm discussion ends up, and to you guys getting onto rigs, rudders and daggerboards.
Appreciate Wess doesn't want to hear about harryproas or non great designers, but the following might help clear up some misconceptions about proas generally. Ignore it if you are fussy about OP's rights.
Some observations:
#16 two boats of equal weight, and different rm will be the same speed, even when one (lower rm) is fully powered up and the other (higher rm) isn't. The only difference will be if flying the windward hull on the fully powered up version reduces the wetted surface. A Tornado loses 10% drag when it flies it's ww hull. A proa with it's much smaller, less loaded hull will gain much less.
#18 Should have said family cruisers. Sorry. There are 11 of these of harryproa style, 25 ish harrys in total. If you identify the 12 large pac proas (I only know of 2, both of which carry a lot of weight in their windward hulls), I will amend my post.
#21 and 23 Cheers, as designed, weighed 2,800 lbs. It's lee hull will displace considerably more than that (about 4,500 lbs). Russ says Jzerro weighs 3,200 lbs (Ryan?). 400 lbs difference, not 1,000.
Cheers only needed the anti capsize pod to stop it capsizing when caught aback and only needed it once. As Wes noted, Jzerro needs it every time the hull is flying and the breeze increases, unless the helmsman takes action.
Cheers lee hull displaces just over 2 tons. The skipper (Tom Follet) knew when to back off because the ww hull started flying or the lee one started nosediving. His seamanship and sailing skills were incredible.
The difference between a large hull designed to carry it's loads, and a small one which is overloaded (water ballasted and floating) is huge. Which is why Ryan is extending Jzerro's and harryproas don't slam and shake.
#29 Awesome photo of Jzerro. From one of the guys (Dave Culp) who sailed on it. Sailed upwind with 2 x 225 lb guys perched on the ww hull and near full ballast tanks (another 500 odd lbs, 430 kgs total), and were still overpowered enough in 22-25 knots true breeze under jib and main to bury the pod and had to rapidly round up and ease sheets.
#30 Thanks for the weight Ryan. What was in it? did you weigh the other hull? If so, what was in it? Thanks also for the experience based information. Clears up a lot of the arguments over the years.
#31 A harry with both hulls in the water has about as much tendency to round up as a cat does to bear away when the hull flies. ie, little or none. This can be seen in the video at
where the rudders are both aligned fore and aft. I think the rudders, their location, the lack of a daggerboard and case in the windward hull, the hull shape (no rocker) and no overloading all contribute.
If you look at the video in post #32 of the proa questions thread, Jzerro has as much turbulence from it's ww hull as it does from it's leeward one. Given that the rudders are in the lee one, this indicates a very draggy ww hull if it is only carrying 25% of the boat weight.
By comparison, the wake from the ww hull (60% of the boat weight) is less on the harry (3 minutes into the video). If the rudders are included in the lee hull turbulence, it is much less. This boat has blunt bows and draggy rudders (both since changed) and weighs 2-3 times as much as Jzerro.
#33 Paul has. Team Pure and Wild. Looks gorgeous. Built and sailed by the best in the world for the Race to Alaska. Sponsored and hyped to the max.
From their facebook page:
"an innovative boat that elevated the level of discussion regarding boat design to a level i have never seen before except perhaps regarding the winged keel"
suddenly became
​"getting rest was going to be virtually impossible since the boat demanded the near full time attention of both crew in anything over 6 knots."
​​
Why? ​Apparently
both crew had to squat/stand on the low freeboard ww hull​ to stop the boat falling over as it had insufficient righting moment​. They wanted a third person, but he would have slept in the lee pod, lowering rm even further. This is probably the least analysed high profile boat failure in the history of SA.
​#50 Ogives are great for proa foils and boards, not so good for rudders. We used them (300mm chord) on a kite proa. Rough shape and finish, but flew ​~200 kgs at ~12 knots boatspeed. The kite was attached to the lee hull, so all the flying force was provided by the foil.https://vimeo.com/127926604 With 2 angled foils like these under the long hull, changing the angle of attack may not be required as the lift increases/decreases as the foil rises/falls. Something to try one day.
#52 The easy way to provide pitch stability is to extend the bows. Higher speed, less pitching, no need for crew movement, scissoring or adjustable foils.
#57 Set it up so shunting is easy (no headsails, either a schooner or a ballestron on unstayed mast(s) and simple rotating rudders), make the short hull big enough (and with an 11:1 or better length:beam ratio) to carry it's designed load so it's not "all draggy" and and put the accommodation there to maximise righting moment and comfort. Longer, lighter, no water ballast, more room, rm and sail area, much less likely to capsize than the G32, which is a very innovative little boat.

 

Share this post


Link to post
Share on other sites

 

Appreciate Wess doesn't want to hear about harryproas or non great designers, but the following might help clear up some misconceptions about proas generally. Ignore it if you are fussy about OP's rights.

 

 

Harryproa - Let me apologize as I can see my comment - along come Rob Denny and essentially splits the middle with the Harryproa which has the weight to windward but the rig to leeward. Forgive me Rob, but please allow me without passing judgment, to ignore this type for the moment (and later in the same post using the adjective "great" in describing Brown and Newick w re Pacific and Atlantic proas respectiverly) - in the first post came across far differently than was intended. The comment was intended to try to smooth the waters re the Atlantic vs Pacific type debate and not as a value judgment on the Harryproa designer, or the design and I am sorry if that was not clear. I was just hoping to avoid the vitriol that comes from others and especially JO when the Harryproa topic comes up. And besides my primary interest had nothing to do w Harryproa but rather was to 1.) see if a tacking type proa was realistic and offered any benefits, and 2.) to better understand the flying pacific proa type and any benefits it might offer (relative to cats/tris/atlantic proa) as a large single-handed racing platform... because while the benefits and general design of the cat or tri or atlantic proa are intuitive to me the pacific flying proa is not other than in a small canoe where crew represents significant moveable ballast. Wess

Share this post


Link to post
Share on other sites

 

 

Would need Ian to confirm and don't think its exactly half half but again, its about a 3000lb boat and I recall a set of beams and float being near 700lb (both sides about 1300). Welcome correction if that is wrong.

 

 

OK, but is that 3000lb for an empty boat? Say it is and you add three crew. Then beams and ama end up being 20% of the weight. How much of that is beams and how much ama? So say the ama weighs 12% of the original F27 + crew weight, and the beams 8%. But we lost 20% of the original weight, so the ama now weighs 15% of the updated weight, and the beams 10%. In your scenario, the ama carries its own weight, and roughly half the weight of the beams, the other half being carried by the main hull. So the resting load on the ama should be 20% of the reduced weight of the tacking outrigger in racing trim. A lot closer to what you proposed than I thought.

 

I thought Inigo Wijnen had commented on how his tacking outrigger Gaia 2 behaved on Atlantic and Pacific tacks, but I can't find the text. Does anyone else remember this?

 

 

That would be an interesting read. Please post it if you locate same. Wess

Share this post


Link to post
Share on other sites

OK, but is that 3000lb for an empty boat? Say it is and you add three crew. Then beams and ama end up being 20% of the weight. How much of that is beams and how much ama? So say the ama weighs 12% of the original F27 + crew weight, and the beams 8%. But we lost 20% of the original weight, so the ama now weighs 15% of the updated weight, and the beams 10%. In your scenario, the ama carries its own weight, and roughly half the weight of the beams, the other half being carried by the main hull. So the resting load on the ama should be 20% of the reduced weight of the tacking outrigger in racing trim. A lot closer to what you proposed than I thought.

Good to get detailed. Take the bare weight given for JZERRO, add gear and three weeks of provisions for two crew, sail it across an ocean. Send us a postcard.

 

 

I thought Inigo Wijnen had commented on how his tacking outrigger Gaia 2 behaved on Atlantic and Pacific tacks, but I can't find the text. Does anyone else remember this?

http://www.pacificproa.nl/gaia2.html

 

I decided on a tacking proa as I had limited experience in sailing proa's overseas.

grimg007.jpg

 

 

Gaia's Dream, a bigger and later boat, is a serious proa!

http://www.pacificproa.nl/dream.htm

  • Loa: 21.6 meters (71 ft)
  • Boa: 11.5 meters (38 ft)
  • Draft boards up no cargo: 0.4 meters (1,3 ft)
  • Draft boards up cargo: 0.7 meters (2,3 ft)
  • Draft boards down: 2.5 meters (8,2 ft)
  • Displacement in passenger mode: 9 tons
  • Displacement in cargo mode: 17 tons
  • Working rig: 132 square meters

http://iniwijnen.com/gaiasdream/

 

morningbay.jpg

layout.jpg

from_above.jpg

Share this post


Link to post
Share on other sites

That is a cool boat. But! The Captain's cabin, the Living area, and engine room are gone in the bottom plan shot!

 

Mutiny Mr. Christian?

Share this post


Link to post
Share on other sites

That is a cool boat. But! The Captain's cabin, the Living area, and engine room are gone in the bottom plan shot!

 

Mutiny Mr. Christian?

 

Looks to me like the gap around the engine where the solar cells are, to windward of the cockpit, got a shelter fitted later?

Share this post


Link to post
Share on other sites

I did find that one, but it is not what I was looking for. I thought I had seen a report on how the boat moved in a seaway on Atlantic and Pacific tacks, and how safe either tack felt in heavy weather. I can't find that on Inigo's site, and I couldn't find it through a web search, either, not with my search terms.

Share this post


Link to post
Share on other sites

That top view of Gaia's Dream shows how its rudder tiller linkages are connected at roughly ninety degrees, push-pull.


This video has many fine details on Jzerro, sailing:

Share this post


Link to post
Share on other sites

That is a cool boat. But! The Captain's cabin, the Living area, and engine room are gone in the bottom plan shot!

Mutiny Mr. Christian?

So too are the fore and aft jibs on furlers. It all got put on later.

Share this post


Link to post
Share on other sites

Here is a tacking outrigger on Kauai, safety ama on starboard side, sailing ama on port side, 45':






Tangent drift - Canoe Sailing Leleuvia Island Fiji with Steve and Mandy West

Share this post


Link to post
Share on other sites

gaias dream had the cabin put on later,

also the (cassette?) balance rudders were extended -> quite the opposite direction of the bieker/brown jester proa design which has a very small rudder area

the furlers where later added. to get her going out of a shunt easier i believe

 

<iframe width="560" height="315" src="https://www.youtube.com/embed/iS270ousYwg"frameborder="0" allowfullscreen></iframe>

Share this post


Link to post
Share on other sites

The AYRS crowd being who they were, you don't suppose McAlpine-Downey entertained the idea of a foil pulling the float down?

No idea. But Dave Culp pointed out (in a discussion elsewhere) that a hold-down foil will depress the hull or foils that carry the load, increasing drag as much as the equivalent weight on the same lever arm, and on top of that is the induced drag from generating that foil force. Therefore in a steady state, a hold-down foil can be expected to be slower than ballast. A 500 metre course plus run-up may well be close enough to steady state, with the deviations manageable by human power, that weight is preferable.

 

If you want a boat that doesn't need constant attention when things are not steady, a stabilising foil may be faster than carrying the amount of ballast and sail area appropriate to the worst conditions you expect could hit before you can do something about it. It will also depend on how sensitive the boat is. A boat with plenty of reserve stability from weight distribution would not benefit from a foil that stabilises by holding down the weather side. A boat that is sensitive to weight distribution might. Judging by what people say about the benefits of getting the boat balanced just right, hold-down foils should benefit Pacific proas a lot more than Atlantic or Harry.

 

If you rely on a foil to keep you the right way up, you may want to think about how common plastic bags and fishing nets are, that might mess up the flow over the foil.

Share this post


Link to post
Share on other sites

 

The AYRS crowd being who they were, you don't suppose McAlpine-Downey entertained the idea of a foil pulling the float down?

 

No idea. But Dave Culp pointed out (in a discussion elsewhere) that a hold-down foil will depress the hull or foils that carry the load, increasing drag as much as the equivalent weight on the same lever arm, and on top of that is the induced drag from generating that foil force. Therefore in a steady state, a hold-down foil can be expected to be slower than ballast. A 500 metre course plus run-up may well be close enough to steady state, with the deviations manageable by human power, that weight is preferable.

 

If you want a boat that doesn't need constant attention when things are not steady, a stabilising foil may be faster than carrying the amount of ballast and sail area appropriate to the worst conditions you expect could hit before you can do something about it. It will also depend on how sensitive the boat is. A boat with plenty of reserve stability from weight distribution would not benefit from a foil that stabilises by holding down the weather side. A boat that is sensitive to weight distribution might. Judging by what people say about the benefits of getting the boat balanced just right, hold-down foils should benefit Pacific proas a lot more than Atlantic or Harry.

 

If you rely on a foil to keep you the right way up, you may want to think about how common plastic bags and fishing nets are, that might mess up the flow over the foil.

An argument for lake sailing. :)

Share this post


Link to post
Share on other sites

 

The AYRS crowd being who they were, you don't suppose McAlpine-Downey entertained the idea of a foil pulling the float down?

 

No idea. But Dave Culp pointed out (in a discussion elsewhere) that a hold-down foil will depress the hull or foils that carry the load, increasing drag as much as the equivalent weight on the same lever arm, and on top of that is the induced drag from generating that foil force. Therefore in a steady state, a hold-down foil can be expected to be slower than ballast. A 500 metre course plus run-up may well be close enough to steady state, with the deviations manageable by human power, that weight is preferable.

 

If you want a boat that doesn't need constant attention when things are not steady, a stabilising foil may be faster than carrying the amount of ballast and sail area appropriate to the worst conditions you expect could hit before you can do something about it. It will also depend on how sensitive the boat is. A boat with plenty of reserve stability from weight distribution would not benefit from a foil that stabilises by holding down the weather side. A boat that is sensitive to weight distribution might. Judging by what people say about the benefits of getting the boat balanced just right, hold-down foils should benefit Pacific proas a lot more than Atlantic or Harry.

 

If you rely on a foil to keep you the right way up, you may want to think about how common plastic bags and fishing nets are, that might mess up the flow over the foil.

You may argue that this proves your point, but the Slatts 22 hydrofoil outrigger flies the ama in hold down or hold up mode. Hand controlled-

 

https://m.youtube.com/watch?v=tzPYbzbdOTg

 

Edit- my old stomping grounds in the video. One of the few days in Seattle without rain. ;)

 

Ah, Lake Sailing!

Share this post


Link to post
Share on other sites

Okay, so much for the old theory (old wives tale non-based on experience), that Sail Rocket missile, you know the worlds fastest sail boat, 65 knots, achieved by that brilliant team.... but it has a hold down foil to windward.

Did I say worlds fastest wind powered craft? Will say it again. You can mouth the words silently. WFWPC.

Sorry boffins, need to upgrade your fairy tale beliefs.

Share this post


Link to post
Share on other sites

Okay, so much for the old theory (old wives tale non-based on experience), that Sail Rocket missile, you know the worlds fastest sail boat, 65 knots, achieved by that brilliant team.... but it has a hold down foil to windward.

Did I say worlds fastest wind powered craft? Will say it again. You can mouth the words silently. WFWPC.

Sorry boffins, need to upgrade your fairy tale beliefs.

Look again Groucho, it is a windward lifting foil with the tip bent down through 90 degrees. The main top windward canted section lifts the windward sponsons and fuselage clear of the water, the tip provides the lateral resistance to the rig. There is no overall down force (and peanuts at that) on that foil until the windward canted section of the foil is clear of the water. If they really wanted downforce, they would have canted the whole foil off to leeward.

 

SailRocket's principle could also be applied to a conventional proa as well, to fly an ama sooner and safer, because if the foil pops, you still have the ama weight to bring you down.

 

 

post-118275-0-19544600-1491087152_thumb.jpegpost-118275-0-23484100-1491087164_thumb.jpeg

Share this post


Link to post
Share on other sites

That looks to be pulling down about as much as a moth setup lifts up foilng to windward.

 

Be that as it may, Slattebo was nice enough to let me sail the Slatts more than a few times, but getting the float out of the water in pull down mode was noticeably faster. You can see in the Duck Dodge footage, so you don't need to take my word for it.

 

Controlling the lift in the foil was fun. Good feel.

Tiny bit of lag.

Share this post


Link to post
Share on other sites

My Raptor also had the Bruce foil that I removed for an active ballast system. I found in many tests it was faster overall on the course. Since I could dump or fill the ballast in less that 90 seconds if needed it could be done while tacking.

 

With the foil you need speed to work so many times with full sail I would capsize before getting the speed needed to hold the ama down. Now between the roller furling sail and the amount of ballast needed I can go on both tacks in complete control without worrying about capsizing. It has worked very well and makes it comfortable to sail in heavier winds.

 

Also with the foil it was such a delicate touch between the optimum angle and causing drag when you went over that amount.

With the wind shifts and gusts it was too hard to control the angle with extension handle it had.

 

With the water ballast I just roller furled the sail to the right size for the conditions and added just enough ballast to keep it steady. I used the mainsheet or traveler for gust control.

 

In heavy air I might have a sliver of sail up and maybe 1/2 a tank ballast. I can go on either tack without having to change the amount in the tank. I am still doing 5-7 knots upwind but in a nice relaxed state.

Share this post


Link to post
Share on other sites

Okay, so much for the old theory (old wives tale non-based on experience), that Sail Rocket missile, you know the worlds fastest sail boat, 65 knots, achieved by that brilliant team.... but it has a hold down foil to windward.

Did I say worlds fastest wind powered craft*? Will say it again. You can mouth the words silently. WFWPC*.

Sorry boffins, need to upgrade your fairy tale beliefs.

*on water.

Share this post


Link to post
Share on other sites

Rob, there are two sections to Sailrocket's foil; the upper, angled outwards section lifts conventionally as the boat gets up to speed, the lower cavitating high speed, sharp pointed foil, chopped off after section, the foil that angles inwards, takes over and holds the platform level once the boat has passed 45 knots. The upper conventional section is not being used at this very high speed. As I see it the important high speed foil is locking the platform down. Remember the team have been understandably very coy about passing information about this important foil; we don't know the subtleties of the design. Also I'm very sure that after the original Sail Rocket took off into the sky that the team would not want a repetition of that dangerous event.

Oh, one thing that many don't realize, a foil can be angled outwards from the platform and provide lift same as the more conventional infacing foil position. I tried this many years ago on Groucho.

ps:You're correct, Stinky, land and ice yachts are faster than Sail Rocket.

post-100779-0-26992300-1491125110_thumb.jpg

Share this post


Link to post
Share on other sites

My Raptor also had the Bruce foil that I removed for an active ballast system. I found in many tests it was faster overall on the course. Since I could dump or fill the ballast in less that 90 seconds if needed it could be done while tacking.

 

With the foil you need speed to work so many times with full sail I would capsize before getting the speed needed to hold the ama down. Now between the roller furling sail and the amount of ballast needed I can go on both tacks in complete control without worrying about capsizing. It has worked very well and makes it comfortable to sail in heavier winds.

 

Also with the foil it was such a delicate touch between the optimum angle and causing drag when you went over that amount.

With the wind shifts and gusts it was too hard to control the angle with extension handle it had.

 

With the water ballast I just roller furled the sail to the right size for the conditions and added just enough ballast to keep it steady. I used the mainsheet or traveler for gust control.

 

In heavy air I might have a sliver of sail up and maybe 1/2 a tank ballast. I can go on either tack without having to change the amount in the tank. I am still doing 5-7 knots upwind but in a nice relaxed state.

Do you miss the foil at all?

Share this post


Link to post
Share on other sites

It was fun at first but either the wind picked up or got gusty and the foil did not have enough down force to correct. As the ama went up less of the foil was in the water making it worst. In perfect conditions it was a blast but now I can fine tune the ballast weight to have the ama just off the water. After all the experimentation and different setup's it is now the most comfortable way to sail. I always get asked where my laptop is when sailing past the monohull fleet:)

 

I will post some videos this year showing how it sails with my Speedpuck aboard.

 

33792908485_8d04580471_c.jpgIMG_3323 by evanbelkom, on Flickr

Share this post


Link to post
Share on other sites

Rob, there are two sections to Sailrocket's foil; the upper, angled outwards section lifts conventionally as the boat gets up to speed, the lower cavitating high speed, sharp pointed foil, chopped off after section, the foil that angles inwards, takes over and holds the platform level once the boat has passed 45 knots. The upper conventional section is not being used at this very high speed. As I see it the important high speed foil is locking the platform down. Remember the team have been understandably very coy about passing information about this important foil; we don't know the subtleties of the design. Also I'm very sure that after the original Sail Rocket took off into the sky that the team would not want a repetition of that dangerous event.

Oh, one thing that many don't realize, a foil can be angled outwards from the platform and provide lift same as the more conventional infacing foil position. I tried this many years ago on Groucho.........

Groucho,

 

Thanks for the clarification, I am aware that the two different sections do different jobs and that they would not have used the same section throughout the length of the foil..... The bottom section is probably wedge shaped with the outer face parallel with the longitudinal centreline.

 

Re windward canted foils, my Proa has one on the ama for lift, but it can also be canted to leeward for downforce. I will post details once it is in the water, which isn't too far away now....

 

post-118275-0-90597800-1491146148_thumb.jpeg

Share this post


Link to post
Share on other sites

Ed, thanks for the replies. Hope I'm not being thick, :) but the whole L shaped foil moved to develop lift on the Raptor

vs the Slatts had a T that only moved the horizontal foil? (Except for deploying) If that is true, I can see why the Raptor mechanical system would be slow to adjust. I wonder if flow hysteresis might be part of the problem on the L foil? Flow discontinuities at the elbow of an L foil must get tricky....

 

And that is reason I didn't buy a Slatts-

I felt that sitting out would be more entertaining & immediate in control, rather than sitting in the main hull, Having had IC experience, I was imagining a hiking plank running between the hulls on parallel longitudinal tracks. Gary Djierking (spelling?) did something like that w/o tracks a few years back that looked good. But Slattebo always looked under control when he was piloting the Slatts. And he was really good at being a little ahead of the curve.

And given the slight lag in control input to foil reaction, It seemed It required a different set of sailing skills.

 

Not comfy as your setup.

 

Did your average speed go up with water ballast, while peak speeds declined?

Share this post


Link to post
Share on other sites

Amati

 

The average speed went up as I had better control in windy conditions. In lighter air I was consistently 1-1.5 knots faster with the water ballast when I also had the foil installed. I was able to test using either one or both combined. After a season of testing all parameters I removed the foil as using the water ballast alone gave me the best overall performance.

This season I will be able to see what the last improvements I did will effect the performance on all points of sail. With the Speedpuck you will be able to see the true speeds I am doing at those points of sail.

Share this post


Link to post
Share on other sites

Thats a pretty cool boat you got there EdVB. Who designed her?

Share this post


Link to post
Share on other sites

AmatiThe average speed went up as I had better control in windy conditions. In lighter air I was consistently 1-1.5 knots faster with the water ballast when I also had the foil installed. I was able to test using either one or both combined. After a season of testing all parameters I removed the foil as using the water ballast alone gave me the best overall performance.This season I will be able to see what the last improvements I did will effect the performance on all points of sail. With the Speedpuck you will be able to see the true speeds I am doing at those points of sail.

Might it be fair to generalize that getting rid of wetted surface would seem to matter more at low speed, and when you have enough stability and therefore horsepower, wetted surface and wave making don't seem to matter as much? Is the crossover around 1 to 1.3 * square root of your waterline length(s)? Or maybe what Norwood implied in his book 'high speed sailing' with skinny hulls~ 1.5-1.7 * the square root of the waterline length?

 

This fascinating. Thanks for the real world info!

Share this post


Link to post
Share on other sites

Wess

 

John Slattebo designed it as a Raptor 16. I did major modifications in the years I had her to what it is today. Some worked and some did not. The link below shows what I did up to 2011. After that I modified the sail and fitted a new aluminum daggerboard. I also added the Speedpuck and hand tiller so I can lay on the tramp to sail or when I want to stretch my legs. The overall weight ready to sail is 160 Lbs. but is pretty much bulletproof now.

 

It seems like many older guys like Meade like sailing a smaller size boat for ease of use. I also found that out coming from my F24 many years back. I can launch or retrieve in 5 minutes and go in 6" of water. It also goes well in light air. I also plan on getting a electric drive for when I am over 5 miles out and the wind dies completely . I can paddle all day at 2.5 knots but it would be nice just to lower the drive and go 3.5 knots till I get close to my destination. For me it has everything I need to go for a quick sail whenever the mood strikes.

 

 

http://www.raptor-uk.net/guests/eddievb/comments1.html

 

23112834891_5089c1e680_c.jpgIMG_0154 by evanbelkom, on Flickr

Share this post


Link to post
Share on other sites

Amati

 

Since the main hull is 17'6" long by 13" wide and the ama just kisses the water there is very little drag so it moves right along in the lightest of air. Once you hit a puff you accelerate and are gone. It really is a blast to sail and with all the controls available you can tweak to your hearts content:)

Share this post


Link to post
Share on other sites

Okay, so much for the old theory (old wives tale non-based on experience), that Sail Rocket missile, you know the worlds fastest sail boat, 65 knots, achieved by that brilliant team.... but it has a hold down foil to windward.

Did I say worlds fastest wind powered craft? Will say it again. You can mouth the words silently. WFWPC.

Sorry boffins, need to upgrade your fairy tale beliefs.

Exactly which fairy tale beliefs? If you don't say, I can only guess.

Share this post


Link to post
Share on other sites

 

 

The AYRS crowd being who they were, you don't suppose McAlpine-Downey entertained the idea of a foil pulling the float down?

 

No idea. But Dave Culp pointed out (in a discussion elsewhere) that a hold-down foil will depress the hull or foils that carry the load, increasing drag as much as the equivalent weight on the same lever arm, and on top of that is the induced drag from generating that foil force. Therefore in a steady state, a hold-down foil can be expected to be slower than ballast. A 500 metre course plus run-up may well be close enough to steady state, with the deviations manageable by human power, that weight is preferable.

 

If you want a boat that doesn't need constant attention when things are not steady, a stabilising foil may be faster than carrying the amount of ballast and sail area appropriate to the worst conditions you expect could hit before you can do something about it. It will also depend on how sensitive the boat is. A boat with plenty of reserve stability from weight distribution would not benefit from a foil that stabilises by holding down the weather side. A boat that is sensitive to weight distribution might. Judging by what people say about the benefits of getting the boat balanced just right, hold-down foils should benefit Pacific proas a lot more than Atlantic or Harry.

 

If you rely on a foil to keep you the right way up, you may want to think about how common plastic bags and fishing nets are, that might mess up the flow over the foil.

You may argue that this proves your point, but the Slatts 22 hydrofoil outrigger flies the ama in hold down or hold up mode. Hand controlled-

 

https://m.youtube.com/watch?v=tzPYbzbdOTg

 

Edit- my old stomping grounds in the video. One of the few days in Seattle without rain. ;)

 

Ah, Lake Sailing!

Thanks for posting that Amanti.

Share this post


Link to post
Share on other sites

The city used to be swarming with sailboats.

 

Does anybody play hooky and go sailing on a sunny day?

Share this post


Link to post
Share on other sites

I will!

 

Living on Lake Winnebago in Wisconsin I saw a great decline in sailing. There are still the Tuesday night races but less people show up.

 

The good thing is as we get older we have more time on our hands but slowing down kind of makes it even.

 

I found out you need a machine that is easier to launch and to be able to do it solo as most of your friends really do not care to do it anymore.

 

Being retired I worry more where I can launch and what the launch fee's are.

 

But once I am on the water with some wind it really does not matter what direction I go. I can dial in the excitement with the roller furling sail and active water ballast. With the modifications I made in the last two years it only takes less than a minute to right and practice it once in a while on a hot day to stay competent.

 

The ultimate is on a steady breeze day getting everything setup and just flying the ama for a long distance upwind at 7-8 knots is a worthy feeling. At 35 degrees to the wind it is not too shabby in my book.

 

I have plenty of drinks to prevent hydration onboard and if need be I can always call my soulmate to meet me with the trailer in case I venture too far and do not want to sleep on the cot that night. I have the minimum aboard always for those kind of days.

 

Sure the F24 would be more comfortable but I still have some adventure spirit in me after all these years:)

 

It is just a different lifestyle that I am glad to experience in my retirement years.

Share this post


Link to post
Share on other sites

http://www.raptor-uk.net/

04_Cuan_Sound.jpg



Sailing begins at 1 min. 47 secs.

By the way, John Slattebo, inventor of the Raptor 16 (HydroVisions), entrusted me with scanning this B/W print image he had obtained:

A landing with canoes, Jaliut, Marshall Isles
Herman Stolpe, Bishop Museum Archives, Honolulu, Hawaii
Marshall Islands Proa

http://pacificproa.com/micronesia/marshall_isles_proas.html

marshall_isles_proas_1000.jpg

 

 

This is a link to high resolution version: http://pacificproa.com/micronesia/marshall_isles_proas_lg.jpg

Share this post


Link to post
Share on other sites

Apart from Cheers all the proas that have been discussed have sloop rigs with 2 jibs. What is the reason for this? Having 2 jibs seems inconvenient, why haven't more proas adopted uni-rigs like so many other high performance multis?

 

The rigs too also all appear to be very straight and in column, are they canted or raked in any way when switching between tacks?

Share this post


Link to post
Share on other sites

Traditional proas moved the base of the spar, the sail's leading edge, from one end of the boat to the other. Gaia's Dream does that to some extent by moving the base of the mast forward in a slot. The stayed sloop rig on JZERRO is well tuned but conventional in most respects.

 

"uni rigs"? Nothing wrong with having two jibs. When opposite tacks require different sails, dropping one and raising the other is very organized:

Mbuli used an unstayed schooner rig. Rigs and proas, two different subjects really. Well, I can see how that happens...

 

Proa-David-Howie_New-Zealand.jpg

Share this post


Link to post
Share on other sites

Pretty much every way to possibly balance the rig has been tried, except for the ones that haven't. With a conventional bermuda rig, raising / lowering jibs is pretty simple if you're not doing it often.

 

Lot's going on in the Marshall photo. The mast is canted forward (to the right) since the crabclaw rig was tacked down to the right when she came ashore. Moving the lift point on the upper spar to the right balances the single sail on that tack. No jib required.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now