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70' Cruising Proa....Big Red Yacht


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2 hours ago, TwoBirds said:

 

Rob has created this Backwinding Myth, it's a conn he uses to attack other designers work for the sole purpose of selling his boats, and if the reactions seem childish it's because after over a decade of Robs bullshit people have gotten beyond tired of it.

If you pull your nose out of Robs ass and take a look at the pics in this thread you'll see that all the boats have some support on the leeward side, except for Robs.

 

you're right, there is some leeward support, but usually the staying angles are narrow enough that freestanding masts seem worth consideration. i don't care about all the history, just interested in the boats, and especially for long distance cruising where crash gybes happen. 

i'll go clean my nose now.

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It's happened one time in 10K miles of sailing Jzerro and this was due to an abrupt wind shift under a rain shower in the Gulf while sailing to Cuba.  I dropped the jib, lowered both rudders and put t

I'd rather you went away. I don't see the benefit to you of an ongoing public, lie-strewn war and it's embarrassing to me. Without you, Rob I wouldn't get the hairy eyeball on these forums. I'm not se

This thread has gone the way I thought it would. Rob is going to bash it over the head with his vindictive form of logic, but for what purpose? He's quoting things that I didn't write, some that were

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The one thing that pisse me off about proa forums is that those who have an opinion seem so fucking one eyed they end up getting their tits in a tangle when a differing view is offered.  To me I don't really give a fuck about who's right and who's wrong.  I just find the concept hugely interesting.  And my opinion ; I believe the Harryproa is well thought out and is an excellent cruiser due to free standing rigs and potential load carrying ability.  While the Pacific proa seems very performance oriented with little load carrying ability and near zero internal room and seems to me anyway to be very tippy. 

In case anybody is wondering yes I have done a gazillion miles on multihulls.

So all you keyboard warriors get off your fucking high horses take a couple of bex powders and have a little lie down.

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13 minutes ago, basildog said:

To me I don't really give a fuck about who's right and who's wrong.

I care.  Truth matters, especially when sailing upwind off a lee shore.  No proa can match the load carrying ability of a catamaran of the same length.  

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7 hours ago, bigmarv said:

you're right, there is some leeward support, but usually the staying angles are narrow enough that freestanding masts seem worth consideration. i don't care about all the history, just interested in the boats, and especially for long distance cruising where crash gybes happen. 

i'll go clean my nose now.

Sorry, I shouldn't have gone off on you.

Your right, free standing masts do deserve some consideration, and there is nothing wrong with Rob's boats as far as I know, Rob on the other hand kills proa threads regular basis, and since he's posted on boatdesign.net that he likes it when proa threads blow up because it generates hits on his website I have to assume that he does so on purpose.

2 hours ago, basildog said:

I find it quite amusing that you hold strong opinions on the subject yet if I'm correct - JZERRO is not my boat, I've never owned a proa.  Ypou sir are a complete fuckwit.

I've never owned a space ship but I'm quite passionate about the space program, what's your point?

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3 hours ago, basildog said:

So all you keyboard warriors get off your fucking high horses take a couple of bex powders and have a little lie down.

If you scroll up you'll find that this thread was going swimmingly till Rob showed up, that's actually fairly normal for proa threads, Rob likes to cause shit because he thinks it generates hits on his website.

 

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16 hours ago, basildog said:

The one thing that pisse me off about proa forums is that those who have an opinion seem so fucking one eyed they end up getting their tits in a tangle when a differing view is offered.  To me I don't really give a fuck about who's right and who's wrong.  I just find the concept hugely interesting.  And my opinion ; I believe the Harryproa is well thought out and is an excellent cruiser due to free standing rigs and potential load carrying ability.  While the Pacific proa seems very performance oriented with little load carrying ability and near zero internal room and seems to me anyway to be very tippy. 

In case anybody is wondering yes I have done a gazillion miles on multihulls.

So all you keyboard warriors get off your fucking high horses take a couple of bex powders and have a little lie down.

You're doing the exact thing that pisse you off about proa forums.  I do own Jzerro, so if you have questions about sailing the boat PM me.  

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Seems to me that any proa thread or forum should encourage all the input that can be had. Surely we are all capable of sorting out which information can help us/inform us and which can't. 

I have never found Rob's stuff particularly disruptive, nor anyone else's.  There are clearly flat earth and round earth camps in the proa debate.

Shunt on. 

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On 9/30/2020 at 9:40 PM, ProaSailor said:

... No proa can match the load carrying ability of a catamaran of the same length.  

No, but it can potentially outmatch the the load carrying ability of a catamaran of equal weight while maintaining similar performance. The advantage of proas is that the optimised weight distribution allows a greater hull length for the load carrying hull. Proas and other multihulls should be compared based on equal weight.

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5 hours ago, Mal Smith said:
On 9/30/2020 at 4:40 AM, ProaSailor said:

... No proa can match the load carrying ability of a catamaran of the same length.  

No, but it can potentially outmatch the the load carrying ability of a catamaran of equal weight while maintaining similar performance. The advantage of proas is that the optimised weight distribution allows a greater hull length for the load carrying hull. Proas and other multihulls should be compared based on equal weight.

I agree that equal weight is a more meaningful comparison than length.  The advantage (greater hull length for the load carrying hull) applies only to the Pacific proa configuration and is lost when half or more of total weight is in the windward hull at rest (or low angles of heel) because both hulls must carry substantial weight depending on conditions.

That being said, catamarans (and trimarans) can have wide flat bottoms aft that carry weight very well and reduce pitching.  I made this animation many years ago comparing a 43' catamaran to a 69' proa (both have similar weight) and a 59' catamaran.  The proa is 26 feet longer than the 43 foot catamaran which is great for performance,  but the "small" cat has more accommodation space.  A "fat", lower performance proa carries more load but doesn't help accommodation that much.

cat_proa_animate-s.gif.fe8d9d3fb61e11a856e902746bcb1bbb.gif

Also, these old images are at the same scale, a 70' proa and a 42' catamaran (28' difference) with similar displacement, accommodation, sail area and cost:

proa_vs_cat-proa.gif.693284911850b21f815f1e7aacc219eb.gif proa_vs_cat-proa_plan.gif.dfad16efb94099994d2578c42c790c99.gif

proa_vs_cat-cat.gif.832f16780e943132faaf5214b651c244.gif proa_vs_cat-cat_plan.gif.c3d5486472b5b8e223ddfcb4c461278f.gif

 

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2 hours ago, ProaSailor said:

I agree that equal weight is a more meaningful comparison than length.  The advantage (greater hull length for the load carrying hull) applies only to the Pacific proa configuration and is lost when half or more of total weight is in the windward hull at rest (or low angles of heel) because both hulls must carry substantial weight depending on conditions.

I would argue that it also applies to Atlantic proas, perhaps to a lesser degree than for Pacific proas. An Atlantic proa is more easily compared to a trimaran with one ama removed. The material from the missing ama can be added to the remaining hulls for extra length. I'm also working on the assumption that equal weight means equal accommodation (payload).

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1 hour ago, Mal Smith said:

I would argue that it also applies to Atlantic proas, perhaps to a lesser degree than for Pacific proas. An Atlantic proa is more easily compared to a trimaran with one ama removed. The material from the missing ama can be added to the remaining hulls for extra length. I'm also working on the assumption that equal weight means equal accommodation (payload).

Like catamarans, and unlike Pacific proas, an Atlantic proa requires both hulls to be capable of comfortably supporting the entire weight of the boat.  So in my opinion, the claim is definitely to a much lesser degree, if true at all.  A catamaran has much more useable space in both hulls than any Atlantic proa I've ever seen, and along with other advantages, good ones sail very well.

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the Atlantic proa loses out in overall weight because the crossbeams have to be MUCH heavier  as they need to be able to support the weight of the heavy hull, which means you need a bigger rig to push the extra weight which means you need heavier cross beams to support the extra weight of the bigger rig, it's a spiral.

pacific proas on the other hand run the same spiral in reverse, the crossbeams can be lighter because they only have to support the ama which means the rig can be smaller as it has less parasitic weight to push.

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55 minutes ago, TwoBirds said:

the Atlantic proa loses out in overall weight because the crossbeams have to be MUCH heavier  as they need to be able to support the weight of the heavy hull, which means you need a bigger rig to push the extra weight which means you need heavier cross beams to support the extra weight of the bigger rig, it's a spiral.

pacific proas on the other hand run the same spiral in reverse, the crossbeams can be lighter because they only have to support the ama which means the rig can be smaller as it has less parasitic weight to push.

Not to mention the larger leeward hull required for an Atlantic to work well.

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missed that, also that with backstays the crossbeams of the pacific proa work in compression rather than deflection when the ama comes out of the water = more weight saved.

 

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45 minutes ago, r.finn said:

Not to mention the larger leeward hull required for an Atlantic to work well.

Isn't that what I said?  Not that it's larger than a Pac proa's leeward hull but with a Pac proa, the leeward hull is the main hull and the only one required to be "large".

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1 hour ago, TwoBirds said:

missed that, also that with backstays the crossbeams of the pacific proa work in compression rather than deflection when the ama comes out of the water = more weight saved.

If your beams are only designed for compression you're going to have a bad time the first time you go aback in a breeze, unless your rig just lets go in some way.

Regarding the rest of the thread, Russell's boats were enormously inspiring to me when I first read about them. Rob's boats were enormously inspiring to me when I saw pictures of them on the internet. Both of them seem to me to be seriously original and well thought out.

Rob was on the yahoo group proa_file years ago when I was first thinking about building a boat. I'd never done any more than patch a hole in my Hobie cat after getting t-boned or fix a soft deck, I had no idea what I was doing building a boat. He was enormously helpful, he wrote out long descriptions of how to do work, what to look out for, how to think about making a part strong enough and light enough. So the idea that all he does is show up and "destroy threads" seems quite off to me.

I get that his self-promotion is offputting to some people. I skim over it, I've already read a lot about Harryproas :)

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41 minutes ago, KONeill said:

I get that his self-promotion is offputting to some people. I skim over it

What do you get about "offputting"?  Did you not notice the repetitive lies?  Or just not care and skimmed over them too?

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56 minutes ago, KONeill said:

If your beams are only designed for compression you're going to have a bad time the first time you go aback in a breeze, unless your rig just lets go in some way.

I get that his self-promotion is offputting to some people. I skim over it, I've already read a lot about Harryproas :)

I had always assumed that the whole purpose of those cables running from below the ama attachment points back to the main hull under the tramp on most blue water proas were the modern version of the mast prop and just for the above mentioned situation, could be wrong though.

I don't have the least bit of problem with Robs self promotion, it's his relentless campaign of lies and misinformation against other designers and other designs that I object too.

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2 hours ago, ProaSailor said:

Isn't that what I said?  Not that it's larger than a Pac proa's leeward hull but with a Pac proa, the leeward hull is the main hull and the only one required to be "large".

I was replying to Two Birds, so...

 

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7 minutes ago, ProaSailor said:

So what?

I think he was pointing out that the spiral I mentioned was even steeper because an Atlantic proa has to be able to carry any extra weight on either hull.

My point about standing rigging was that it does a lot more on a Pacific proa than hold up the mast, and absolutely nothing at all on an Atlantic proa.

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5 hours ago, TwoBirds said:

I had always assumed that the whole purpose of those cables running from below the ama attachment points back to the main hull under the tramp on most blue water proas were the modern version of the mast prop and just for the above mentioned situation, could be wrong though.

I don't have the least bit of problem with Robs self promotion, it's his relentless campaign of lies and misinformation against other designers and other designs that I object too.

I've never been super fond of the idea of waterstays, but ok, that would work. I don't know if most blue water proas have them, do they?

My point was just that you should plan for going hard aback in a breeze, it's going to happen eventually. I haven't crossed any oceans in a proa but I've sailed a few thousand coastal miles in a 20'er. I've gone aback twice, once in a real breeze. You have to build the boat to survive that even if it only happens once.

I'm not getting into adjudicating who's telling lies and who's not. This argument is twenty years old, it's not going to be settled here.

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The antagonistic fighting bullshit is what inspired rob's decades long quest to discredit any and all proas that didn't have an H in front of them. I'm partly responsible, but only because I really dislike false advertising and also because it was hard to have my lifetime work in proas discredited. It wasn't smart to fight back, but I say let rob's work speak for itself and please don't fucking fight about this shit. It's stupid.

Ryan Finn is likely the worlds most skilled proa sailer at this point in time, so maybe just appreciate what he has to say.

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12 hours ago, KONeill said:

If your beams are only designed for compression you're going to have a bad time the first time you go aback in a breeze, unless your rig just lets go in some way.

That touches on a question that has been bothering me for years, so seeing that there are people in this thread with enough knowledge to answer, perhaps someone is willing.

The traditional Pacific proa designs range from having almost equal hulls to using a log as ama that is barely afloat when at rest.  Their modern descendants avoid the barely afloat ama, even though it seems to have some advantages.  I read an article by John Shuttleworth that tried to quantify how a wave can capsize a multihull, and two important factors were the area and shape of the weather hull on which a breaking crest could get a grip, and its volume.  An ama that barely floats has the minimum area to be hit by a wave, and minimal volume to lift it, so that should provide the multihull most resistant to wave-induced capsize so long as the waves come from the intended direction.  And it would provide minimum stability when caught aback. 

All the modern Pacific proas I have seen have amas that are perhaps 20% immersed when at rest, or less.  (That is judged only by eyeballing, so the figure may be off, but there is still more volume out of the water than immersed.)  So if that ama provides a righting moment of X Nm when in the intended orientation, why does it need to provide 4X Nm when the boat is caught aback?  And if the beams are dimensioned for that, they need to be correspondingly heavier.  Is there some dynamic effect I am overlooking?  The only idea I had for that was the ama being lifted out when going upwind, then coming down.  If the reserve volume is too small, perhaps there is a risk of the ama diving deep enough for the beams to hit the water.  Is that it, or something else?

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good question, I've read that the islanders would fill their hulls with water to survive a bad blow if they were caught out, not sure how that'd work though, my experience with a boat full of water has been surprisingly unstable,  but I've never tried a proa full of water.

The traditional proas didn't need any stability when caught aback as the rig just blew over on it's canting mast.

Traditional proas were mostly used in the lagoons and between nearby islands, the big double canoes were used for voyaging. I suppose you could consider modern proas a hybrid of the two designs, which makes sense as they're meant fulfill both roles.

I suspect the variations in ama design reflect the local conditions in which they were developed, on many atolls almost every outing started and ended in massive breakers making wave resistance a priority.

The materials at hand had a huge influence on proa design as well, their wood was so awful a European shipwright would have had a hard time making a decent raft out of it, and their tools were made out of sharp rocks, fire hardened wood, and seashells.

The construction of a medium sized proa often took the labor of an entire atoll for a full season to finish, probably why some of their boats had nicer houses than their owners :)

11 hours ago, KONeill said:

I've never been super fond of the idea of waterstays, but ok, that would work. I don't know if most blue water proas have them, do they?

My point was just that you should plan for going hard aback in a breeze, it's going to happen eventually. I haven't crossed any oceans in a proa but I've sailed a few thousand coastal miles in a 20'er. I've gone aback twice, once in a real breeze. You have to build the boat to survive that even if it only happens once.

I'm not getting into adjudicating who's telling lies and who's not. This argument is twenty years old, it's not going to be settled here.

Ahh, I see what you mean, I thought it went without saying, my point about the crossbeams operating under compression when the ama comes out of the water saves beefing up the crossbeams to support any ballast in the flying ama as one would have to do with an un-stayed rig.

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5 hours ago, WetSnail said:

That touches on a question that has been bothering me for years, so seeing that there are people in this thread with enough knowledge to answer, perhaps someone is willing.

The traditional Pacific proa designs range from having almost equal hulls to using a log as ama that is barely afloat when at rest.  Their modern descendants avoid the barely afloat ama, even though it seems to have some advantages.  I read an article by John Shuttleworth that tried to quantify how a wave can capsize a multihull, and two important factors were the area and shape of the weather hull on which a breaking crest could get a grip, and its volume.  An ama that barely floats has the minimum area to be hit by a wave, and minimal volume to lift it, so that should provide the multihull most resistant to wave-induced capsize so long as the waves come from the intended direction.  And it would provide minimum stability when caught aback. 

All the modern Pacific proas I have seen have amas that are perhaps 20% immersed when at rest, or less.  (That is judged only by eyeballing, so the figure may be off, but there is still more volume out of the water than immersed.)  So if that ama provides a righting moment of X Nm when in the intended orientation, why does it need to provide 4X Nm when the boat is caught aback?  And if the beams are dimensioned for that, they need to be correspondingly heavier.  Is there some dynamic effect I am overlooking?  The only idea I had for that was the ama being lifted out when going upwind, then coming down.  If the reserve volume is too small, perhaps there is a risk of the ama diving deep enough for the beams to hit the water.  Is that it, or something else?

I don't know much about traditional proas. The best book I've read on the traditional boats was Gladwin's East Is A Big Bird, which is great on a couple of different levels. From what I understand if you went aback the rig fell down. I have no idea how a boat with a sinker ama would act in big weather, I just don't know.

The reason I have a big, floaty ama with a lot of volume: My boat originally had a very small ama and very light beams. The ama was about 120 lbs volume total, the beams were 10' Laser topmast sections. This made for a very small boat. You could only sit on the main hull. If you sat out at all, even in a big breeze, you'd get dunked repeatedly, and the stress on the boat was huge. Once in a breeze I tried to sit over the ama and just keep the power cranked on and I got dunked to my waist three or four times in five minutes, I thought I was going to break the boat. So you had to sit in near the main hull, and the "boat" was the big hull, it was like sailing a canoe with a bench seat and a big arm out behind you:

http://wikiproa.pbworks.com/f/messabout2003-7.jpg

When I built the new 8.5' beams I also built a new ama:

http://wikiproa.pbworks.com/f/ama on boat r.JPG

It's about 650lb or 700lb of volume.

Now you can sit wherever you want. It makes the boat feel huge. Now it's like a beach cat, you can sprawl on the tramp and not worry about sinking the ama. Two big guys can sit over the ama, it's fine.

I think this is a reason even pretty small western proas have higher volume floaty amas. It makes the boat a lot bigger. If a 20' boat is as big as you want to drag around on a trailer, a sinker ama makes it feel like a little 20' canoe with one seat, it's tiny. A floaty ama makes it feel like a beach cat. The increased size is huge.

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6 hours ago, WetSnail said:

All the modern Pacific proas I have seen have amas that are perhaps 20% immersed when at rest, or less.  (That is judged only by eyeballing, so the figure may be off, but there is still more volume out of the water than immersed.)  So if that ama provides a righting moment of X Nm when in the intended orientation, why does it need to provide 4X Nm when the boat is caught aback?  And if the beams are dimensioned for that, they need to be correspondingly heavier.  Is there some dynamic effect I am overlooking?  The only idea I had for that was the ama being lifted out when going upwind, then coming down.  If the reserve volume is too small, perhaps there is a risk of the ama diving deep enough for the beams to hit the water.  Is that it, or something else?

If a proa’s ama is say 20% displacement and you have set sail so that the ama is “skimming”, and righting moment is maximised, if you are caught aback, you need the ama to have the original 20% displacement plus at least another 20% to have the same righting moment “aback”. Less than that and the ama could be driven under with all that could follow. Which is one shortcoming of the Atlantic proa configuration. Hard pressed and suddenly caught aback, there is much less righting moment, and capsize is possible.

With such a small (displacement) ama there is a good chance upwind or downwind, of waves catching the ama connectives If not the beams themselves which is wet, noisy, slow and adds shock loading.

Some amas have storage to maximise usable volume in the main hull for accommodation and increased righting moment.

In principle, you are right. The name of the game is to maximise the LWL of the leeward hull. Any “spare” ama hull material could be better used in extending the leeward hull. Shorter amas also means there is less catamaran like cork screwing motion upwind in waves.

FWIW, Sidecar has a ~25% total displacement ama with another ~75% reserve buoyancy and is used for storage. Ama length is ~66% LWL. I carry my batteries (I have electric auxiliary power) spare gear and consumables including fishing rods and sun canopy/shade awning out there, and the batteries at least need to stay dry. It is hard to keep water out if the deck is often awash especially at speed, so extra freeboard and volume helps and keeps the hatches and connectives out of the waves.

 

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On 10/3/2020 at 2:53 AM, ProaSailor said:

Like catamarans, and unlike Pacific proas, an Atlantic proa requires both hulls to be capable of comfortably supporting the entire weight of the boat.  So in my opinion, the claim is definitely to a much lesser degree, if true at all.  A catamaran has much more useable space in both hulls than any Atlantic proa I've ever seen, and along with other advantages, good ones sail very well.

There are a lot of variables, so it's difficult to compare one configuration to another. I suggested using weight, by which I mean total displacement, because it roughly corresponds o both cost and utility. For instance, if you utilise the available volume in the catamaran for extra accommodation, you are adding extra weight, so you have to scale down the catamaran to bring the displacement back into line.

Getting back to the issue of the Atlantic proa hull length, the advantage of the Atlantic proa compared to a catamaran is the increased righting moment. If the overall beam of the cat and the Atlantic proa is similar, you can obviously use the increased righting moment to carry more sail. On larger boats though, the righting moment of a catamaran is more than adequate, so an alternative is to reduce the overall beam of the proa to achieve the same righting moment as the cat. This reduces the weight of the connecting structure and that reduction can be added as extra hull length.

BTW, I'm not against pacific proas at all, but I do have a bit of an interest in Atlantic proas, having built a small one back in the 90's.MI6-Proa-01.thumb.jpg.bf8676f750ebf6d75fb7e286c68d7bf7.jpg

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On 10/3/2020 at 5:19 PM, Sidecar said:

If a proa’s ama is say 20% displacement and you have set sail so that the ama is “skimming”, and righting moment is maximised, if you are caught aback, you need the ama to have the original 20% displacement plus at least another 20% to have the same righting moment “aback”.  ...

With such a small (displacement) ama there is a good chance upwind or downwind, of waves catching the ama connectives If not the beams themselves which is wet, noisy, slow and adds shock loading.

...

FWIW, Sidecar has a ~25% total displacement ama with another ~75% reserve buoyancy and is used for storage. Ama length is ~66% LWL. I carry my batteries (I have electric auxiliary power) spare gear and consumables including fishing rods and sun canopy/shade awning out there, and the batteries at least need to stay dry. It is hard to keep water out if the deck is often awash especially at speed, so extra freeboard and volume helps and keeps the hatches and connectives out of the waves.

So if not being flipped by a wave were my primary design consideration, I should have an ama like Splinter's (https://epoxyworks.com/wp-content/uploads/2015/10/splinter1-e1495550700432.jpg), half submerged at rest, and perhaps rasing the beams a bit more?  And if I want the freeboard, but not a big volume, make the ama narrow, especially above the waterline?

On 10/3/2020 at 4:43 PM, KONeill said:

I have no idea how a boat with a sinker ama would act in big weather, I just don't know.

The reason I have a big, floaty ama with a lot of volume: My boat originally had a very small ama and very light beams. The ama was about 120 lbs volume total, the beams were 10' Laser topmast sections. This made for a very small boat. You could only sit on the main hull. If you sat out at all, even in a big breeze, you'd get dunked repeatedly, and the stress on the boat was huge. Once in a breeze I tried to sit over the ama and just keep the power cranked on and I got dunked to my waist three or four times in five minutes, I thought I was going to break the boat. So you had to sit in near the main hull, and the "boat" was the big hull, it was like sailing a canoe with a bench seat and a big arm out behind you:

If you can get to a place with surf in reasonable time, a simple test should give some idea.  Make two voluminous lee hulls from a plastic bottle or two each, or whatever else is convenient.  Tape on a pair of sticks.  Then tape on a piece of wood to the weather side of one of them, and another plastic bottle or two to the weather side of the other.  Ballast with sand.  Put both in surf and start comparing the number of capsizes.  The problem would be to find surf of just the right size that the largest waves capsize one of the models about half of the time.  Maybe make the beam adjustable.  Then ballast the high volume ama model until it capsizes at the same rate as the low volume model, and compare righting moments, and perhaps rotational inertia.

So far, I take that as two people saying the ama sinking enough for the beams to catch the waves is the problem, one of whom experienced the problem, the other avoided it. 

 

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On 10/3/2020 at 2:27 AM, WetSnail said:

All the modern Pacific proas I have seen have amas that are perhaps 20% immersed when at rest, or less.  (That is judged only by eyeballing, so the figure may be off, but there is still more volume out of the water than immersed.)  So if that ama provides a righting moment of X Nm when in the intended orientation, why does it need to provide 4X Nm when the boat is caught aback?

If the ama at rest carries 25% of total boat displacement with a reserve buoyancy (volume above the waterline) of just three times that (or less), then fully immersed would be 100% displacement of the whole boat (or less, 4 * 25%), which sounds like a reasonable safety factor to me if backwinded.  A Pacific proa's ama that is lifting out of the water and plunging back down would be more gentle with more rocker (lower prismatic) and a V bottom instead of a flat or rounded bottom.

fish7637.jpg

Source: http://pacificproa.com/micronesia/flying_proas_of_the_Ladrone_Islands.html
link to full size image: http://pacificproa.com/micronesia/fish7637.jpg

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12 hours ago, Mal Smith said:

BTW, I'm not against pacific proas at all, but I do have a bit of an interest in Atlantic proas, having built a small one back in the 90's.MI6-Proa-01.thumb.jpg.bf8676f750ebf6d75fb7e286c68d7bf7.jpg

Malcolm, I've admired your work and had links to your web pages from my Proa Web Sites page for as long as I can remember:

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2 hours ago, WetSnail said:

So if not being flipped by a wave were my primary design consideration, I should have an ama like Splinter's (https://epoxyworks.com/wp-content/uploads/2015/10/splinter1-e1495550700432.jpg), half submerged at rest, and perhaps rasing the beams a bit more?  And if I want the freeboard, but not a big volume, make the ama narrow, especially above the waterline?........

So far, I take that as two people saying the ama sinking enough for the beams to catch the waves is the problem, one of whom experienced the problem, the other avoided it. 

Waves hitting amas and catching connectives/beams will always be a greater or lesser problem, depending on the conditions you mostly sail in, so anything, whether it be reserve volume, freeboard and/or the connective design themselves which minimises wave contact and impact is worth considering.

Sidecar’s ama is small by modern standards and was designed to minimise both, but it still has contact at times. And I would rather have less.

Interesting to see that the modifications to Paul Beiker’s (Pure and Wild) proa also includes changes from direct beam/ama  connections to connectives. Possibly for strength and stiffness also?

Take inspiration also from some more traditional craft.

4BEC05DC-A9F2-46E5-ACA5-2F89328D713E.jpeg

stretched proa 2-1.jpg

4CF74A75-4686-4279-B3D9-093032FC1063.jpeg

82CCB732-2621-48AC-84AF-5886188DE891.jpeg

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On 9/29/2020 at 7:29 PM, Happy said:

I don't really understand the animosity. Rob never misses an opportunity to promote his ideas, and he doesn't mind an argument. So what? Original thinkers usually rub people the wrong way. I prefer to focus on the boats.

I've been following the Harryproa evolution from the beginning, back when the Aussie multihull magazine was printed in black and white on cheap grey newsprint, and the internet was only for scientists.  I like the concept for a light, simple cruising boat. Not as pretty as a Pacific proa, probably not as fast, but more comfort and more ease of operation.

Unstayed weathercocking rigs make excellent sense for less skilled and less racy owners. My main worries are infusing full-length parts. Rob reckons it's as easy as sitting down to piss, but he's done it a thousand times.

The other thing that Harryproa sailing videos show is a wet ride. If I was considering building one, I would definitely want spray rails and slightly higher bows.

Not a thousand infusions yet, but the current project has been going for 56 days.  We have built moulds for and infused 10 hull/deck panels (4 x 12m/40' (2 more next week), 6 x 9m/30' ), 4 by 3m/10' rudder halves, 4 x 2m bulkheads incl hollow stringers and many samples and test pieces for various items including some interesting truss beams made from fibreglass rods and a reefable wing rig.  

We have tried a bunch of new things, including flax instead of f'glass and stringers instead of foam core (hopeless and great, respectively), sundry panel joins, minimising consumables and recycling/reusing those we do use.      A few minor repairs, no throw away panels and mostly perfect laminates with ~half the resin and none of the suiting up, gloves, mess, fairing and waste from hand laminating.   see http://harryproa.com/?p=3788 and https://www.facebook.com/Harryproa/?ref=page_internal for details

Not quite as easy as "taking a piss", but I am working with half a dozen volunteers with no prior boat building or composite experience.  After helping with 2 infusions, they can do them on their own.  

The Harryproa plans have all the instructions you need to infuse panels, rudders, beams and masts, starting with small samples and working up to the big ones.   The plans are drawn by Steinar, who probably holds the record for the largest amateur infusion,  his 20m/66' lee hull), which was his first infusion after several tests.  He probably also has the record for remoteness as he is building on a Norwegian island north of the Arctic Circle.   http://harryproa.com/?p=726 

39584337_ScreenShot2020-10-04at10_44_11am.png.011ba74e8556933a6fb14c05c90e388b.png

 

Re wet bows:

The videos show the Mk 1 bows, which were very full as back then it was 'common knowledge' that proas sail bow down (most of them do, apparently).  With experience from the built boats, and rockerless hulls, we have found this to be not true for Harryproa hull shapes, so the latest versions are sharper ended. eg http://harryproa.com/?p=1747    Even with the full bows, the spray off the lee hull bows blows to leeward, so it is not a big deal for the crew and passengers.  A couple of owners actually like it.  The rudders are the other source of spray, the price you pay for the peace of mind that comes with rudders that kick up in a collision.  They have been  considerably streamlined on recent boats, and the cargo proa can mount them on the lee side, which will make them even less obvious.    

High bows are necessary if you have to go forward at sea or have hull shapes with insufficient buoyancy forward.  Otherwise they are weight and windage in the worst spot possible apart from the rig.

Two Birds,  

I did not create the gybing in a breeze blowing the stick away "myth".  Wooden Boat and Cruising World did, read the articles in post #38.   Have a look at the staying angles and the mast's capacity to take the large compression loads generated by the much greater than normal rm and much smaller than normal staying angle and you will see it is not a myth.   

Re web hits:

You have confused cause and effect.   The more  I post information about Harryproas and design/build innovations, the more web hits I get.  You guys and your irrational dislike keep giving me opportunities to post this information.  Feedback is that potential clients like the way I keep the conversation on boats and sailing, regardless of how much mud is flung at me. They think it shows that I am a reasonable person (which I am), with whom it is easy to discuss their dream boats even if they don't eventually choose a Harryproa.  

Re "people who have forgotten more than i will ever know": 

There are many people with more proa miles than me, but I'm pretty sure no one who has posted so far has designed, built or sailed on as many different types and sizes of proas, from traditional through to the 24m/80' cargo proa mentioned above.  Plus 40 years selling materials to and advising amateur and professional boat builders.   I have also done a little offshore racing (including 7 Sydney Hobarts, one on a 40' trimaran), was a trans Pacific and Atlantic catamaran delivery skipper in the days before gps, have capsized 2 racing cats (one in the North Atlantic) and have sailed on boats which hit a whale (keel damage) and a sunfish (broken rudder) at high speed.    I consider this experience to be more valuable in designing safe, fast and easy to build and sail proas than thousands of offshore miles in a single type.   

The videos show the 7.2m/24' plywood  Mini Cargo harryproa which a group of Marshallese Islanders spent a month building under my supervision earlier this year and me sailing on, and shunting, a traditional canoe, which is not as easy as it looks.    Notice the steering paddle use on each.   Top speed on the Mini Cargo proa so far is 13 knots, with 5 large Marshallese and their fishing gear on board.    Despite appearances, the 2 of us did not go appreciably faster than this on the traditional boat, which did not sail up or down wind anywhere near as well as the Mini Cargo proa.  

 

 

 

Re lies:

You and the Harry haters carry on about "the lies I tell about other designers and their boats".   I don't tell lies.    If you think I have,  please reference them (ie, what I said, and when and where i said it, why it was wrong) so I can correct them and apologise.  Thanks.

Russ,

You started flinging the anti Rob mud in post #40, rather than addressing the topics in the articles.   You ignored the abuse while your fan club continued to dish it out.  Now people with experience are repeating the drawbacks (beam design, caught aback and gybing issues, rudder damage when running aground, righting moment, jibs on bows, etc) that I have been pointing out for years, and those who know me are saying I am a nice guy.     Suddenly, after 10 years of trolling me and instigating it,  you ask for the fighting to stop.  Could these 2 things be related?

Wet Snail.

Good question, I wish there were more like it.  

From my experience, the answers are:

Caught aback buoyancy to avoid the hull sinking.   This is only required if the beams and rig are designed to lift the entire weight of the lee hull, in which case, these components are far heavier than they need to be 99% of the time.    

Keeping the crew dry if the boat is set up to sail it from the windward hull, which makes more sense than sitting on the lee hull and pumping water ballast to get righting moment.

Allowing the crew to board, fish, etc from the windward side.

Keeping the beams clear of the water. It is easier to make straight beams and a higher hull than curved beams, especially if the beams telescope.

To provide enough reinforcement for a daggerboard, which from a reducing weather helm point of view,  would be better off in the lee hull.  And from a safety point of view, _on_ the lee hull so it could kick up in a collision or grounding.    

The canoe in the video had near zero buoyancy in the kubaak (the ww hull, the Marshallese I spoke to were pretty pissed off culturally with westerners using their terminology for boat parts which are nothing like the originals, such as ama, aka, vaka, etc).  However, the rig falls down if caught aback, so this is not a big deal, unless you are sitting where it falls, or the rig is too big to manhandle back up.  As with everything on these boats, there is a technique.  I could just manage to raise the rig in light air.  One of the old guys raised one about 50% larger with less effort than it took me on the stripey sail.  He also shunted single handed as if it was a ballet performance. Spar in one hand, 3 steps, turn, 3 steps, drop the spar in the other bow.  Maybe 3 seconds, compared to our grunt and hope technique.

Mal,

Have you still got MI6?  Have you made any changes?  It was runner up in a design competition I sponsored when I was importing System Three epoxy,  a  detail Joe might want to add to his web page.  ;-)

Rob

 

 

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On 10/5/2020 at 1:09 AM, TwoBirds said:

looks quick, bet she turned some heads.

On the half a dozen occasions that we sailed it, it was pretty quick. It was particularly quick in light airs, and it was a pleasure to sail. As with all development work though, there were teething problems that needed to be sorted. We had gone into it with the foolish idea that we could make business out of it. Unsurprisingly, we weren't able to attract any investors for the further development work we needed to do and we moved on to other things.

21 hours ago, harryproa said:

Mal,

Have you still got MI6?  Have you made any changes?  It was runner up in a design competition I sponsored when I was importing System Three epoxy,  a  detail Joe might want to add to his web page.  ;-)

Rob

 

 

Rob,

The boat is currently languishing in Ian's mums backyard. I'm not sure what state it is in, I haven't seen it for over 20 years. Ian reckons it's still OK. We will need to move it soon I would think, so It might end up down here in Bowral, as a retirement project for me to sort out. Mainly It needs a new boom as we broke the forward wishbone last time we sailed it. I also want to change the swing rudders for dagger rudders. Ideally I would change out the aluminium beams for a Farrier style folding system and if I was redesigning it I would carry the main hull sponsons all the way to each bow to allow overnight camping sleeping space.

I think you will find that we won the design competition. First prize was the epoxy and coretech panels that we used to build the boat and start us on he slippery slope.

Cheers, Mal.

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On 10/4/2020 at 5:50 PM, harryproa said:

 

I did not create the gybing in a breeze blowing the stick away "myth".  Wooden Boat and Cruising World did, read the articles in post #38.   Have a look at the staying angles and the mast's capacity to take the large compression loads generated by the much greater than normal rm and much smaller than normal staying angle and you will see it is not a myth.   

 

 

the article discusses a possible flaw in the pacific proa, you've quoted it out of context and milked it for sales for the better part of 2 decades, starting about 10 years after Russel fixed it.

 

the second part is a classic example of robs favorite sales technic, I call it Faux Logic, he starts with a lie and then makes up a perfectly logical seeming explanation that covers the lie, he started off with the lie "Pacific proas have no support on the leeward side" I called him on it,. then he made up the lie about mast compression, which he knows full well is a load of crap as pacific proas have the longest staying base and lowest mast compression of virtually any hull form, now he'll take this answer and twist it into another lie, which is why those who are experts on pacific proas refuse to answer his questions, they simply don't want to give him any more ammo to quote out of context later.

I wasn't kidding when I said he's on a relentless campaign of misinformation, and I finally understand why those who love the concept of pacific proas have given up on calling him on his bullshit, unless one is willing to treat refuting his crap like a job and build up a huge complication of posts to copy and paste like rob does there's no real way to do anything about his lies, thing is, pretty much everything rob has ever posted about pacific proas is misinformation, I'd be surprised if the same isn't true about everything he's ever posted about his boats.

 

"On the half a dozen occasions that we sailed it, it was pretty quick. It was particularly quick in light airs, and it was a pleasure to sail. As with all development work though, there were teething problems that needed to be sorted. We had gone into it with the foolish idea that we could make business out of it. Unsurprisingly, we weren't able to attract any investors for the further development work we needed to do and we moved on to other things."

 

Just curious, those teething troubles, was it that thing that atlantics do where the rig wants to be downwind and when it gets there the boat wants to trip over her foils and capsize?

 

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3 hours ago, TwoBirds said:

Just curious, those teething troubles, was it that thing that atlantics do where the rig wants to be downwind and when it gets there the boat wants to trip over her foils and capsize?

If anything, the Mi6 had more weather helm than I would have liked. The rig could have done with being a little further to windward, which is one of the points for further development work. We did capsize the boat once. We were launching off the beach in 25 knots of wind and due to inexperience with the boat, got the rudder lowering/sheeting on sequence wrong, which did lead to a backward capsize.

The teething issues were more around detailed design. One of our goals was quick set-up and launch time and we needed to do more work on that. The boom had been under-designed and we've sorted the design for that but haven't made the new one yet. The main issue though was the rudder design. The rudders are reversible and the boat sails with them both fully down all the time. The rudders are linked through the tiller system so that they turn on opposite directions and if the boat is perfectly balanced the rudder helm loads can exactly cancel each other out, which is nice. We went for a swing rudder system with the idea that the rudder blades would be allowed to trail slightly so that the CLR of each individual rudder was slightly behind the rudder hinge axis. We designed a low friction axle system so that when shunting the rudders would moved back into the correct position as the boat moved off in the new direction. This didn't work and the rudders needed to be 'manually assisted'. Apart from this, the swing rudders were a pain when launching, mainly due to their size but also things like when to beach the boat and then go to relaunch it, you have to take the rudders off and turn them around to go back out. The last time we sailed the boat, we experimented with fixing the rudders in the vertical position while sailing. This seemed to work OK. The helm feels a bit weird as the individual rudders are overbalanced, but it seemed manageable. Hence dagger rudders in vertical cases might be good, simple option.

MI6-Proa-07.thumb.jpg.c865eb04438924f11e52fc3fac29b8d2.jpg

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35 minutes ago, Mal Smith said:

If anything, the Mi6 had more weather helm than I would have liked.

Surprised..... I would have expected some lee helm?

On Sidecar, it is the case that if I sail with just the windward jib, I have (slight) lee helm, if I sail with just the mainsail I have (much heavier) weather helm. Sidecar also tends to have (slight) leehelm DDW, more so with the windward screecher up. Sidecar also gets (slight) leehelm when I reef the mainsail. It is a fine balancing act.

Sidecar has taught me that the transverse relationship of CE and CLR is just as important, if not more so than the traditional longitudinal relationship. It is a bit like pushing a balance trailer ........ The push needs to be in the right place between the wheels.....

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1 hour ago, Sidecar said:

Surprised..... I would have expected some lee helm?

On Sidecar, it is the case that if I sail with just the windward jib, I have (slight) lee helm, if I sail with just the mainsail I have (much heavier) weather helm. Sidecar also tends to have (slight) leehelm DDW, more so with the windward screecher up. Sidecar also gets (slight) leehelm when I reef the mainsail. It is a fine balancing act.

Sidecar has taught me that the transverse relationship of CE and CLR is just as important, if not more so than the traditional longitudinal relationship. It is a bit like pushing a balance trailer ........ The push needs to be in the right place between the wheels.....

Yes, the transverse location of the rig is very important and can be used as a tuning tool. With the Mi6, the main hull displacement is maybe 80% or 90% of the total displacement when loaded, so the 'centre of transverse resistance' (CTR) is quite close to the centreline of the main hull. The true centre of resistance (CR) is the combination of the CTR and the CLR. For transversely symmetrical boats the CTR is usually ignored, but on a proa it's important. The helm turning moment is a function of the distance between the thrust line of the rig and the CR. I have often considered that it would be possible to use a balanced rudder system and swing rig as per the Mi6 on a Pacific proa, if the rig was placed somewhere further out on the akas.

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Hi Russel, there's an animation here of a modified version of the rudder system. It's basically as is, but with the addition of a bar on top of the steering yoke and a double tiller arrangement to simplify shunting the rudders - 

 

There are a few more photos of the boat, but no videos (it was pre-digital age). Somewhere I've got drawings of the rig, which I'm happy to share if I can find them. The rig was aluminium construction. I describe it as a stayed ballestron rig. The lower section of the mast is large diameter and tapers sharply up to the spreaders at wishbone level. Above that level it's just a conventional mast section. Initially it was all one piece, but later (after breaking the mast in our capsize) we modified it so that we could rig the boat upright by putting the lower stump first in and then raising the top section of the mast. The delta shaped jib is mainly to allow shunting without having to duck under a boom. It also looks pretty cool I think. The jib doesn't require sheets, but another mod I would do is to add a cringle to the leach at the wishbone level and add some sheet like lines for backing the jib during a shunt. This would help to shift the CE forward briefly until there is enough flow over the rudders to counteract any weather helm.

MI6-Proa-03.thumb.jpg.9e9ef841df6766ba5d78d80fd630d848.jpg

 

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...While visions of interlocked ruder systems danced through their heads ...  :)

here's a vid of a Pacific proa with interlocking weatherboards, it's a much more basic system than yours, there's a vid of the boat on the beach just showing how the boards work, I'll poke around and see if I can find it. https://www.youtube.com/watch?v=ai  for some reason you-tube won't let me imbed it.

I've never put much thought into Atlantics, I've got a bad back which makes boom dodging interesting and it looks like on an Atlantic you either dodge booms most of the time or throw away a bunch of righting moment by raising the boom high enough to not be a menace to passengers and crew as rob has done on his boats, that's very cool boat though, the idea might be worth coming back to in a few years as proas gain acceptance.

 

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couldn't find the video I was looking for, this one gives a good look at the weatherboards in the last 30 seconds or so.

https://www.youtube.com/watch?v=Jn8fr0PaUqg&t=15s

this guy had some really cool ideas and then just disappeared off youtube  ten years ago, here's a couple videos  of a model of a monoproa, probably not pratical, but very cool.

https://www.youtube.com/watch?v=as4o9Y41gds

https://www.youtube.com/watch?v=vZQjV37gl3E

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I'm glad I asked. My brain couldn't even get past the rig until now. Does the jib ever try to overbalance the main (fill when you don't want it to)? Did the flow and relationship between jib and main look right? How much wind have you sailed it in? I wouldn't ask so many questions, but you seem okay with talking about it. Did you build it for a race?

You obviously went deep down the steering rabbit hole. Steering proa's is a lot like pedal drive systems on R2AK boats. People come up with out-there stuff, but most of them work. Proa's seem to bring out deep thought in anyone who gets the bug and some of the solutions to problems are really quite amazing. I'm mostly over that particular bug, but I'd really like a ride on Sidecar. 

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That is quite a list and what a history! I read something by Guy Delage that was hard to accept, but he has been a big part of the European proa world in the old days. His Funambule proa went 38 knots!

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On 9/13/2020 at 11:29 AM, r.finn said:

What I hate the most about Rob's approach is that he insists on quoting people out of context.  He is a thread burner like DL, and just like DL, the best approach is to ignore and especially not quote them. Neither know what they're talking about but are the first to plant their flag on a topic. For example, below is a video of the boat Rob marketed as an ocean capable race boat?  And he spends much of his time criticizing other Proa designers, who are actually sailing their boats, as in seaworthy!  Get your popcorn ready though, Rob has a pre-packaged victim response ready to be pasted here with some tweaks criticizing me and whoever else calls him on his bullshit.  Enjoy the show! 

 

Good grief.  Proas and its off the rails yet again.  Can't you guys just get along.  All you Joe, Russ, Rob, etc... ever do is throw stone at each other.  Kinda sad as Russ especially is somebody I really respect or want to...

Can you talk sailing instead?  Did you ever do the Clipper Route in a proa (heard about it forever but nothing seemed to actually happen)?  And didn't you give up on proas and head over to minis (love the minis BTW) or is that an different dude with same name?

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1 hour ago, Russell Brown said:

That is quite a list and what a history! I read something by Guy Delage that was hard to accept, but he has been a big part of the European proa world in the old days. His Funambule proa went 38 knots!

I know they have their disadvantages but I can't help but get excited by Atlantics - I guess it was because my introduction to proas was reading 'Project Cheers' many years ago.  I can concede that pacifics may be more elegant structurally but I can only imagine the sensations of blasting along in a fully powered up Cheers or Funambule. 

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1 hour ago, Wess said:

Good grief.  Proas and its off the rails yet again.  Can't you guys just get along.  All you Joe, Russ, Rob, etc... ever do is throw stone at each other.  Kinda sad as Russ especially is somebody I really respect or want to...

Can you talk sailing instead?  Did you ever do the Clipper Route in a proa (heard about it forever but nothing seemed to actually happen)?  And didn't you give up on proas and head over to minis (love the minis BTW) or is that an different dude with same name?

I haven't touched a mini for many years, so that's not me.  As for NY to SF, I'm leaving this winter.  Finishing two more sails and some other projects and then looking to head north next month.  

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1 hour ago, r.finn said:

I haven't touched a mini for many years, so that's not me.  As for NY to SF, I'm leaving this winter.  Finishing two more sails and some other projects and then looking to head north next month.  

All Right !!!

Any place on the web where we can follow your trip? The wordpress home page has not been updated for quite some time, and no, I am not on Facebook...

I still remember this afternoon sail on Jzerro, gliding at 11 knots on flat water, and how, when sailing upwind, lowering the daggerboard in the ama markedly reduced weatherhelm.

Wish you all the best.

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1 hour ago, Laurent said:

All Right !!!

Any place on the web where we can follow your trip? The wordpress home page has not been updated for quite some time, and no, I am not on Facebook...

I still remember this afternoon sail on Jzerro, gliding at 11 knots on flat water, and how, when sailing upwind, lowering the daggerboard in the ama markedly reduced weatherhelm.

Wish you all the best.

I'm not sure how to social media this.  My only sponsors are RBS Battens and Colligo Marine, and these are in kind.  I'll be sending both sponsors updates from the road so they can have content for their own marketing, but no planned updates on my website unless it makes financial sense to.

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On 10/5/2020 at 2:50 AM, harryproa said:

I did not create the gybing in a breeze blowing the stick away "myth".  Wooden Boat and Cruising World did, read the articles in post #38.   Have a look at the staying angles and the mast's capacity to take the large compression loads generated by the much greater than normal rm and much smaller than normal staying angle and you will see it is not a myth.   

I once followed links back to when things blew up between you and Joe.  As I remember it, you two started off friendly, but then Joe said about your first Harryproa that carrying that much weight to weather, on a short hull, would generate unmanageable weather helm.  You responded with what I read as "You don't know, you haven't sailed the boat", but which Joe seemed to read as "You are too ignorant to understand why this is not so."  (If I am wrong, Joe can correct me.)  Having been in the situation where someone who had not sailed your boat told you something that conflicted with your experience, I expected you to have more respect for Russ telling you these articles do not accurately reflect his opinion and experience.  And I understand you making direct comparisons when you first presented your designs to the public and kept getting asked "Why do your boats look so different from Russ Brown's?"  But you could phrase those comparisons less combatively.  There is room for different design philosphies.  The Gougeon G-32 goes against the established design philosophy of maximising righting moment in much the same way as a Pacific proa does, and I haven't seen big disputes over that.

I just looked at the videos in this thread.  Jzerro's boom is too short to hit the headstays, so that would not take down the rig in a gybe.  There are two shrouds attaching to the beams only about a third to windward.  I could see the boom hitting those at speed being a concern.  That would be a problem only in a violent gybe and if the sheet is long enough to let the boom hit those stays.  It would not be a general problem with being caught aback with that rig. 

You think the problem is the staying angle between the headstays.  Will you show your work?  What is the equation for compression load for one unit horizontal load directly from the lee side, as a function of staying angle between head stays?  Does your calculation take into account that those head stays also have a very wide base, which reduces compression load?  Then we can plug in numbers for Jzerro and some catamarans, and see how they compare.

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8 hours ago, Russell Brown said:

I'm glad I asked. My brain couldn't even get past the rig until now. Does the jib ever try to overbalance the main (fill when you don't want it to)? Did the flow and relationship between jib and main look right? How much wind have you sailed it in? I wouldn't ask so many questions, but you seem okay with talking about it. Did you build it for a race?

You obviously went deep down the steering rabbit hole. Steering proa's is a lot like pedal drive systems on R2AK boats. People come up with out-there stuff, but most of them work. Proa's seem to bring out deep thought in anyone who gets the bug and some of the solutions to problems are really quite amazing. I'm mostly over that particular bug, but I'd really like a ride on Sidecar. 

Prior to designing the Mi6 I'd had a lot of experience with swing rigs on model yachts. As long as the main/jib proportions are right, the rig won't overbalance. Essentially the rig behaves as a una rig. In model yacht circles it is generally accepted that swing rigs are twitchier than conventional sloop rigs i.e. the power is either on or off. With a conventional sloop rig you tend to sheet the jib home and then play just the main, which is a bit smoother for controlling the power of the rig. In fact on model yachts they will tend to use swing rigs in light air and sloop rigs in heavy air. As with a una rig, a disadvantage of the swing rig is that you can't use it like a separate main and jib to sail the boat through the shunt, so the inherent balance of the boat needs to be pretty good.

The slot between the delta jib and the main is probably less than ideal, but certainly good enough. The design could undoubtedly be evolved a bit to improve this.

We sailed it a few times in +20 knots, but each time we did, we broke something. In total I think we did less than 20 hours of sailing in it before life got in the way of frivolity. The boat was designed to meet the rules of the design competition that Rob mentioned, which was to design a day boat for a family of four made from System Three Coretech panels. I convinced my Naval Architect friend and colleague Ian Sargeant to help design a proa, because I happened to like proas. I had read 'Cheers' as a teen and had built a small model based on it. Technically the Mi6 can be sailed as a Pacific proa as well, but we didn't try that.

There is an old web page about the boat - http://www.users.on.net/~malcolmandjane/mi6.html

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To continue the thread drift, John Pizzy built and sailed many Proas in Australia, possibly the last of which was a camping trailerable  pacific style "Flight". I vaguely recall a (mid 90s?) test in a sailing magazine that was pretty positive, but can't find it online. What I do recall is that she had a pivoting mast that was somehow connected to the rudders so that during the shunt the mast would tilt forward somehow lifting the old rudder and lowering the new one. She was also self righting due to mast being angled to leeward.

 hull_flying.jpg

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36 minutes ago, Mal Smith said:

I vaguely recall that it's a soft sail. It looks that way in the photo. The AYRS rig has full length battens.

I think the clever bit of Pizzey's rig was a vertical line down the centre of the sail that could be tensioned during the shunt.  It then allowed both halves of the sail to hang downwind in a relatively controlled way while the boat was beam on  to the wind and shunting operations were carried out.  

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The first proa I ever saw (about 1972) was a red 70 footer. It had a jib only rig. Mast in the middle and a jib or Genoa at either end. It was really striking looking and had been to Hawaii and back. The boat was already old when I saw it.

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19 hours ago, WetSnail said:

 

I just looked at the videos in this thread.  Jzerro's boom is too short to hit the headstays, so that would not take down the rig in a gybe.  There are two shrouds attaching to the beams only about a third to windward.  I could see the boom hitting those at speed being a concern.  That would be a problem only in a violent gybe and if the sheet is long enough to let the boom hit those stays.  It would not be a general problem with being caught aback with that rig. 

 

The two shrouds you mentioned attach to the ends of the beam the bench is mounted on and while I don't know what the designer had in mind they would likely stop the boom from swinging over the bench and bopping anyone sitting on it on the noggin.

If the boom did hang up on those shrouds the force would be nearly DDW and place very little strain on the mast and rigging over and above the boom hitting the shroud.

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10 hours ago, Sidecar said:

There are some good stories there, and I've been through them a few times, but can't track the magazine review down. I think he had plans to put "Flight" into production. I might have to look under the house in my piles of old magazines...

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8 hours ago, TwoBirds said:

The two shrouds you mentioned attach to the ends of the beam the bench is mounted on and while I don't know what the designer had in mind they would likely stop the boom from swinging over the bench and bopping anyone sitting on it on the noggin.

If the boom did hang up on those shrouds the force would be nearly DDW and place very little strain on the mast and rigging over and above the boom hitting the shroud.

I think what you saw was the spinnaker halyard. If the main goes aback it does hit the backstay, whether the boom clears or not. This has happened and has been discussed by Ryan and myself from our experiences.

Anyone remember that 70' proa I was talking about? It was in San Diego when I saw it. The ama was 40' and was the main hull from the builder's previous proa. It would be great if anyone remembers it. It was a beautiful boat and it would be great to see a photo.

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On 10/8/2020 at 3:03 AM, Anotherclarkey said:

I think the clever bit of Pizzey's rig was a vertical line down the centre of the sail that could be tensioned during the shunt.  It then allowed both halves of the sail to hang downwind in a relatively controlled way while the boat was beam on  to the wind and shunting operations were carried out.  

Was wondering just how that worked, found it in the info Sidecar posted.

 

"On my soft sails I installed a set of eyelets centrally down the sail to enable a slack flail line to pass therethrough from the masthead to a fore and aft strop along which the lower end could freely move.  This kept the sail under control if released, folded about the flail line, should both sheets be released.  Also when docking, with the sheet released the flail line could be tightened to operate the forward half of the sail, handy at times when just a little slow speed movement is required. The sail could then be reefed by tying up a bottom panel of the sail.  The sail could also be lowered along this flail line. I also used this technique in a spinnaker for Flight, a most tricky undertaking. Ah the stories I could tell about racing and gybing downwind to round a mark, changing the spinnaker set from one end to the other with opposition boats under kites bearing converging to the mark. Try it one day and figure out how many lines etc you need. Again perhaps someone has worked it out and could share it with all who are interested.  A bell-mouth and sock is another good start for controlling the spinnaker. I used that on Pi."

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2 hours ago, TwoBirds said:

Was wondering just how that worked, found it in the info Sidecar posted.

 

"On my soft sails I installed a set of eyelets centrally down the sail to enable a slack flail line to pass therethrough from the masthead to a fore and aft strop along which the lower end could freely move.  This kept the sail under control if released, folded about the flail line, should both sheets be released.  Also when docking, with the sheet released the flail line could be tightened to operate the forward half of the sail, handy at times when just a little slow speed movement is required. The sail could then be reefed by tying up a bottom panel of the sail.  The sail could also be lowered along this flail line. I also used this technique in a spinnaker for Flight, a most tricky undertaking. Ah the stories I could tell about racing and gybing downwind to round a mark, changing the spinnaker set from one end to the other with opposition boats under kites bearing converging to the mark. Try it one day and figure out how many lines etc you need. Again perhaps someone has worked it out and could share it with all who are interested.  A bell-mouth and sock is another good start for controlling the spinnaker. I used that on Pi."

It is such a simple idea but must really help tame a type of rig that many seem to have had considerable trouble with.

What I find fascinating about Pizzey is that he didn't seem to be chasing raw performance (though he often mentions racing the boats) but sensations of sailing that he found enjoyable like flying a hull in complete control, almost as an end in itself.  'Flight' in particular seems more like a G32 than anything else - I wonder if some of his ideas like inclining the rig to leeward (before actual capsize.....) and counter-intuitively angled boards could be used on that boat?

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5 hours ago, Anotherclarkey said:

 - I wonder if some of his ideas like inclining the rig to leeward (before actual capsize.....) and counter-intuitively angled boards could be used on that boat?

Sidecar’s windward jib is inherently canted to leeward, so it has at least some “auto dumping” built in. It also helps the jib/screecher set in light sloppy conditions..... I have yet to try quickly”tacking” the jib when over heeled which theoretically at least should provide extra righting moment and pull the boat pretty smartly around into the wind, depowering the main as well?

Sidecar also had a 2 way asymmetric canting foil. Canted outboard, it does provide some lift, canted inboard, it provided extra righting moment. The loads on the hinge and controls were massive and whilst it could lift the ama at around seven knots, I had the feeling the boat was faster without the board deployed due to the frontal and surface drag of a long narrow foil. It also was a good wave catcher when not deployed and vibrated a lot, changing pitch and frequency with speed, going quiet once the ama had lifted, so I took it off. I may put it back on again once I have the rest of the boat sorted the way I want.......

If you “pop” a windward canted lifting foil, your RM increases back to normal which is safer than “popping” a leeward canting foil, and losing the extra RM created from normal which could cause problems....

In steady conditions, flying the ama early with a canting foil would work well and you have a small safety factor. Conditions here in the Bay and Sound are too unsteady and variable most of the time to put it properly to the test.....

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23 hours ago, Russell Brown said:

I think what you saw was the spinnaker halyard. If the main goes aback it does hit the backstay, whether the boom clears or not. This has happened and has been discussed by Ryan and myself from our experiences.

Anyone remember that 70' proa I was talking about? It was in San Diego when I saw it. The ama was 40' and was the main hull from the builder's previous proa. It would be great if anyone remembers it. It was a beautiful boat and it would be great to see a photo.

There was a large proa moored off the end of Shelter Is (no spars, ever) for many years. Never saw any action on it. It disappeared from that spot about 18 years ago. Sort of a tan hull with some sort of "tribal" decorative band around the gun'l

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29 minutes ago, longy said:

There was a large proa moored off the end of Shelter Is (no spars, ever) for many years. Never saw any action on it. It disappeared from that spot about 18 years ago. Sort of a tan hull with some sort of "tribal" decorative band around the gun'l

That's the one I saw. Probably the first one I ever saw.

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On 10/12/2020 at 12:31 AM, TwoBirds said:

I saw her for sale on gumtree not that long ago. she was looking pretty felorne. 

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On 10/14/2020 at 3:33 AM, TwoBirds said:

I managed to find the full patent application for John Prizzey's proa complete with illustrations which are in a pdf you can download near the top of the application.

 

https://www.freepatentsonline.com/5088431.html

I'm having trouble opening the links, but it looks like there's meant to be a video and a PDF. Are you able to post them directly? 

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here's the pdf, I couldn't find a video US5088431.pdf   US5088431.pdf

some of the patent reference material looks interesting as well, I haven't had a chance to read through them, but the first one, "Sailing Multihull with variable lift" mentions Joseph Norwood.

hope someone bought About Face and fixed her up, looked like a lot of really nice woodwork on her.

 

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Here's a closer photo my wife took of About Face at a wooden boat show in Sydney, late 80's or early 90's, I'm not sure. The name on the side is 'Bosna', so I guess it was still with the original owner. The interesting thing about this boat is that it has the proportions of a Pac