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      Abbreviated rules   07/28/2017

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Wess

Proa question

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Devil in the details, but there you have it. Still favor the rig as tested, easier for most blokes to manage, but likely not a market. I understand the frustration. At best and worst you gave it a shot but remember it's never over 'til the fat lady sings! Hang tough.

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Tink, forgot to ask, in the test vid, boat had square spars.

 

Better than round 6061? I used round, as the NACRAs did, and copied them with same fasteners etc, to make it easier. Thinking back, maybe square or rectangular would have been better choice strategically. Pic of one below. No rush to answer.

post-38311-0-33519000-1492684509_thumb.jpg

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As a side note to this jolly discussion, I am part way through building my test bed ISO dinghy based trimaran.

 

I only have one side made up and usable so I guess it is currently a tacking proa?

 

The trampoline frame slides in and out for easy storage in a dinghy space and it has two vertical bolts that lock it in place through the internal box frame.

 

The wind was very swirly and all over the place for this short test but it gets a shift on and the stability and feeling of security is very good and confidence inspiring. I need to get the outrigger sanded and painted asap as just epoxy at the moment and then make the other side.

 

I'm going to change the design of the next float to compare performance - adding some extra volume and changing the shape but keeping the slender entry point. Further on, I will also make some much smaller lighter floats for when our technique has improved to lighten things up. Finally I will replace the ISO hull with my own designed hull as it is quite weighty and to add various features for our intended fast cruising requirements.

 

The newly welded up frame feels pretty rigid and the home made tramp is working well - I can lie down in comfort or hike and my wife can hike out nicely. I've added a cam cleat for the main sheet on the tramp frame for me and I will add a further one for the jib and hopefully we can get testing the trapezing option as well next time.

 

Unfortunately we had no phone or GoPro again but hopefully next weekend we will be more organised if the weather is any good.

 

We also had to sail back in head to wind down the river and mildly against the tide and the easy tacking with good stability in shifty gusts was great. Still a bit hairy for us as we are very inexperienced but shows we have nothing to worry about.

 

The only GPS run we have had had 11 knots on a reach in low winds and we won't use the spinny until we get the other side sorted. It should fly once we get confident and sort the set up.

 

All in all I'm very pleased: speed and safety for not a lot of cash.

 

In the interim as time is tight to make next frame and float I might just make a little wing extension to get more leverage when hiking out and trapezing.

 

Flame away.

Nice testbed-

 

did the hull plane differently depending on your tack? Does your main hull rise at the nose on plane? How does that effect the ama?

What does the flow around your ama look like at 11k? Does the ama look like it is planing?

Yes the hull plane is very different depending on which tack. Once we were hiking out or sitting in and moving along we had it just skimming. The nose rises even in just a reach and the ama lifted up some as well. The underside of the float is a shallow v to give us some planing potential and immediate bouyancy as soon as it hits the water but it seems to have enough shape to reduce slap. Did high side it once when couldn't release main sheet quickly enough but gave us laods of time to control it and it didn't go over. It was 30 knots gusting up to 35 knots wind though and we were heading back in as that was a bit much for us.

 

We ahve no ability to reef with that sail currently so I am planning on putting in 2 sets of reefing points so we can safely go for longer day trips - round the Isle of Wight etc and not be worried about being caught out as conditions in the Solent can change pretty dramatically. If it works on this crap old sail I will then put them in on the 2 like new sails I got with the boat.

 

Here is a video from a different test in low winds at Mudeford from January 2nd the - frame was just temporarily rivetted for speed but gave us an idea that the dimensions were about what were after.

 

https://www.youtube.com/watch?v=y79a5qejTFY&t=2s

 

It gives a bit of a view of the wake from the outrigger at various points and speedds but that was with it sat pretty heaviliy in the water as although the verticals were shorter we were not making any effort to balance things up as no hiking strap leta lone trpaeze at that point.

 

The inside crossbeam will be removed shortly as now not needed and will save a few kilos.

 

The float is under 20kg and we are pretty light at 55kg and 75kg so I'll check frame and tramp/frame weight to see the new total but we are probably still lighter than quite a few crews....

 

The angle of the float has changed since then and we need to get hiking for balance. As my wife is so small, we can safely both trpaeze off his mast apparently which I think will be great

 

We could look at taking some weight out of the floats - it is rammed with plastic bottles and so on for safety bouyancy to ensure my wife was happy we were not going to sink horribly.... Keep some but what she doesn't know etc...

 

End goal is to d osome safe, fast solo coastal trips.

 

If I am allowed : )

Thanks for the Youtube! The stern wave on both hulls let go cleanly a couple of times in the vid. It was a bit hard to see what happened to the stern of the ama when the main hull started planing- it looks like the bow on your main hull rises on a plane & your ama does too. Does that sink the stern of the ama?

 

FWIW, L Francis Herreschoff said that women have an innate sense about boats that men lack...... :lol:

Vantagexxxx...

 

Nice...I frikken love it as it is...but

 

With many fewer strings and a modified crab claw sail or soft wing, to me, would be orgastic.

 

Sort of what I had in mind when I began current rig, but MO plans and funding locked me in to the current rig.

 

Screw the VMG if it's fun. What raises my flag is the fun and if done right to fly simple. Of course, simple might interest the masses and we wouldn't want that.

 

Sort of reminded me of an ingenious but smaller South African rig called "Ninja" that may have skidded. Fit in a box. I wanted one, but too far off.

 

Where can I see more? Or is testing restricted. Appreciate the vid.

I am ludicrously busy with work as had my main guy walk out with no notice unexpectedly the day before I went on holiday ..... working well over 100 hour weeks currently so testing is very limited. I'm also building a large summer house and getting the old cars ready for the summer but luckily don't need much / if any sleep...

Twice though we've managed to get out recently but not had gps or gopro available but if we can get time this weekend we will def have them on and hopefully if any reasonable conditions can give it a bit more stick and see how it goes. Predicited winds at the moment look pitiful though.

 

I was very interested in the ninja as well - looked simple and intersting and the proa option looked cool. Seems to have died a death after the moulds were sold which is a shame,

 

i will probably also knock up a slender hulled single hander using the same large new floats but with super light main hull so I can go out by myself using the same ISO rig as I have a have a spare mast and sails and that will really shift I expect. I will also put on some foil assist at least to really limit heeling and reduce wetted area but can't see how my time is going to be for the next few months. A proa option like I have now would def be on the cards.

 

My kaymaran also needs a bit more work to make it an easy single hander that I can sail from the trampolines not just from the rear cockpit which means I can't move the weight around by myself losing to much righting moment and with the super small floats limits things (also need to fair in the crossbeam mounts as they scoop water badly currently).

 

Slow in low wind unfortunately but gives an idea:

https://www.youtube.com/watch?v=BQEYzkxGw7A

 

Something then like this with a super narrow hull, more freeboard, totally massive fuck off rig with decent floats and foil assist will be the perfect car topable speed machine...

 

I ripped the leeboard out at some pace last time we were out though so I need to rebuild and mount that better and enlarge the rudder a bit to get quicker turns.

 

Our very first testing of this one with no tramps and in 25knot winds was quite scary - mast looked like it was going to snap in two as had no reefing capabiltiy then, or the jib or the mast stays and it is so much faster now with laods of improvements still to make:

https://www.youtube.com/watch?v=mZTb-kBewE4

 

I need to just downscale the business hugely, sack everyone and go part-time so I can be in the workshop more and get out on the water more : )

Don't know what your business is, but I went from supporting a crowd to a one man shop and made more $$ because my costs went down. Hours reduced too.

 

On a more vexing note, I just had the pleasure of discovering I'm sensitized to Gorilla Glue and Titbond 3 (yes, I was using protective gear, but GG releases a small amount of a complex chemical that can trigger asthma, TB has a different chemical that can also lead to respiratory issues, and both chemicals are hard to filter with even elaborate masks- the upshot is read safety sheets, and assume even rare reactions can occur) so it's Titebond 2 and eternal leak vigilance for me. If this keeps up I'll be hollowing out palm trees with an adze :) . But I'm already sensitized to Western Red Cedar, so there you go.

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And one more proa question while I'm cursing modern ANSI 1 adhesive chemistry, and that concerns rocker- it seems the blokes down under are abandoning rocker for more speed, and I've tried it once and it seemed ok, but design software indicates rising wave resistance with that approach, where normal rocker ( returning back to the waterline at both ends) shows a reduction in wave resistance to zero at hull speed. No rocker on a double ended hull can, for example, get the prismatic from (rockered)~ .49 to (no rockered)~.61 with the same planform- is the higher prismatic more important on a double ended flat bottomed hull that can lift up on a plane and increase it prismatic that way? Or is a flat bottomed double end low prismatic hull just too sucky (Chris Maas coined that one :) ) to get easily on a plane?

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Vantage... I"Tink" I got it right this time...

 

Anyway, I see the round tube inserts into the square frame on boat decking...I think I get it...and I am stuck with what I have. Sorry for misdirection.

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Vantage... I"Tink" I got it right this time...

 

Anyway, I see the round tube inserts into the square frame on boat decking...I think I get it...and I am stuck with what I have. Sorry for misdirection.

What you have got is always best unless you on an AC budget

Round in round is better though

If you putting horizontal pins in it makes little odds

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Vantage... I"Tink" I got it right this time...

 

Anyway, I see the round tube inserts into the square frame on boat decking...I think I get it...and I am stuck with what I have. Sorry for misdirection.

What you have got is always best unless you on an AC budget

Round in round is better though

If you putting horizontal pins in it makes little odds

 

Thanks. I kinda guessed, using what the NACRAs used, for similar sized rigs. Still, wondered if I could have gone with rectangular akas or beams, to make lower. But, as they say, in for a penny, in for a pound, went with the safe side...now going to replace the deck and Hobie 16 ama (outrigger) with a much lighter ( I hope) foam hull. Should alter the rig much. Figure to reduce weight by 70 pounds or approx 31.5 kilos, which of course makes for wetter and higher ride on s'board side...c'est la vie! More like orig, but a few kilos lighter...will have to add spray skirts eventually.

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This Catamaran is 18ft x 14ft and is supposed to make foiling easier. It has a canting rig to provide lift so it can ride better on the foils. I can't imagine how this would tack without coming off the foils and almost stopping. If you are going to use a canting rig there is only one platform that does it with any efficiency - a proa (Vestas sail rocket 2) There where at least two foiling proas with tilting rigs forty years ago (I am away from home so can't give a reference) I am sure a modern take of those boats would be half the weight of this and considerably faster. If I had the time and the money I'd be on it.

 

http://voilavion.com/post-62633-0-34116100-1492715472_thumb.jpg

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This Catamaran is 18ft x 14ft and is supposed to make foiling easier. It has a canting rig to provide lift so it can ride better on the foils. I can't imagine how this would tack without coming off the foils and almost stopping. If you are going to use a canting rig there is only one platform that does it with any efficiency - a proa (Vestas sail rocket 2) There where at least two foiling proas with tilting rigs forty years ago (I am away from home so can't give a reference) I am sure a modern take of those boats would be half the weight of this and considerably faster. If I had the time and the money I'd be on it.

 

http://voilavion.com/attachicon.gifIMG_4666.JPG

Crazyass boat. Reminds me of Rocket rig. Are foils overkill, 'cept to play?...Maybe tack under semi crabclaw...pic is gooseneck for Malibu Outriggers semi CC sail on Gnarly. Independent carbon spars. Heavy sucker.

post-38311-0-38378400-1492723357.jpg

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And one more proa question while I'm cursing modern ANSI 1 adhesive chemistry, and that concerns rocker- it seems the blokes down under are abandoning rocker for more speed, and I've tried it once and it seemed ok, but design software indicates rising wave resistance with that approach, where normal rocker ( returning back to the waterline at both ends) shows a reduction in wave resistance to zero at hull speed. No rocker on a double ended hull can, for example, get the prismatic from (rockered)~ .49 to (no rockered)~.61 with the same planform- is the higher prismatic more important on a double ended flat bottomed hull that can lift up on a plane and increase it prismatic that way? Or is a flat bottomed double end low prismatic hull just too sucky (Chris Maas coined that one :) ) to get easily on a plane?

Your software indicates zero wave resistance at hull speed??? And you aren't skeptical about that???

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And one more proa question while I'm cursing modern ANSI 1 adhesive chemistry, and that concerns rocker- it seems the blokes down under are abandoning rocker for more speed, and I've tried it once and it seemed ok, but design software indicates rising wave resistance with that approach, where normal rocker ( returning back to the waterline at both ends) shows a reduction in wave resistance to zero at hull speed. No rocker on a double ended hull can, for example, get the prismatic from (rockered)~ .49 to (no rockered)~.61 with the same planform- is the higher prismatic more important on a double ended flat bottomed hull that can lift up on a plane and increase it prismatic that way? Or is a flat bottomed double end low prismatic hull just too sucky (Chris Maas coined that one :) ) to get easily on a plane?

Your software indicates zero wave resistance at hull speed??? And you aren't skeptical about that???
I figgered that Dave made an assumption about supersonic flow around a bluff body, but Joseph Norwood did that same thing in his book about fast sailboats- especially trimaran outriggers at higher Froud (sp?) numbers. So skeptical me builds a 16' by 36" hull with the Vacanti modelling software (hey, it's what I have), and the wave propagation was going down a bit (by eye at least) at higher speeds. I don't know what to make of it. I'm skeptical of assumptions in mathematical constructs, but pressure field activity, mathematically, is beyond me. In my own defense, I keep reading masters theses about where modelling logic can spin it's web, but it's still a new discipline, and does represent an opinion, in a very sophisticated sense.

 

E. B. White might agree?

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Apply to proas or outriggers, or even beamy tris?

 

Then along comes a fat scow, blowing by, and foil-less too.

 

Elwin? Boats?

 

Is this is the wrong bay?

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And one more proa question while I'm cursing modern ANSI 1 adhesive chemistry, and that concerns rocker- it seems the blokes down under are abandoning rocker for more speed, and I've tried it once and it seemed ok, but design software indicates rising wave resistance with that approach, where normal rocker ( returning back to the waterline at both ends) shows a reduction in wave resistance to zero at hull speed. No rocker on a double ended hull can, for example, get the prismatic from (rockered)~ .49 to (no rockered)~.61 with the same planform- is the higher prismatic more important on a double ended flat bottomed hull that can lift up on a plane and increase it prismatic that way? Or is a flat bottomed double end low prismatic hull just too sucky (Chris Maas coined that one :) ) to get easily on a plane?

Your software indicates zero wave resistance at hull speed??? And you aren't skeptical about that???

 

I figgered that Dave made an assumption about supersonic flow around a bluff body, but Joseph Norwood did that same thing in his book about fast sailboats- especially trimaran outriggers at higher Froud (sp?) numbers. So skeptical me builds a 16' by 36" hull with the Vacanti modelling software (hey, it's what I have), and the wave propagation was going down a bit (by eye at least) at higher speeds. I don't know what to make of it. I'm skeptical of assumptions in mathematical constructs, but pressure field activity, mathematically, is beyond me. In my own defense, I keep reading masters theses about where modelling logic can spin it's web, but it's still a new discipline, and does represent an opinion, in a very sophisticated sense.

 

E. B. White might agree?

 

Any analogy between supersonic airflow and waves in water is only superficial & there's no reason to think it might be useful for any sailboat calculations. There are other codes available that solve the actual equations of interest (the Michlet code, for example)

.

But regardless of what code you use, a result like zero wave resistance should make you wonder what went wrong.

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Vacanti is a retired Boeing fluid flow guru, and did the calcs for the keel on Amati (which works great). So any assertions on my part viz the supersonic analogy, even based on criticisms I've come across of the software, are without a doubt very superficial! :) Norwood wasn't a lightweight either, so it's difficult to reject what look like non intuitive results out of hand. Lowrider Moth hulls, or the Serenity Windsurfer hulls seem to point in the same direction, and resulted in my own full size experiment. I have a YouTube of my canoe sailing if you'd like, but if I go off SA and link it, I'll get kicked off so I can't edit it back into this post. Let me know...

 

The calcs I've been looking are in displacement mode and the results are expressed in wave drag in pounds. Only certain shapes give wave drag in pounds going back to zero. If you're interested, you can download a trial sample of the software off the web for free. I don't remember if that gives wave and friction drag, but if you're interested, Google Vacanti Yacht Design Software.

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My Cross 42R trimaran had a funky 'constant section area' themed hull/keel that was a carryover from Norm's time an Conair or Convair as an aeronautical engineer. That was what led to the 'wasp waisted' fuselages of which the F-102 was probably the best example. The 'area rule' which led to that feature apparently only works in a compressible medium (air) and didn't help drag or wave generation at the air/water interface.

 

Quote from Wiki on the F 102

 

To solve the problem and save the F-102, Convair embarked on a major redesign, incorporating the recently discovered area rule, while at the same time simplifying production and maintenance.[15] The redesign entailed lengthening the fuselage by 11 ft (3.35 m), being "pinched" at the midsection (dubbed the "Coke Bottle configuration"), with two large fairings on either side of the engine nozzle, with revised intakes and a new, narrower canopy. A more powerful model of the J57 was fitted, and the aircraft structure was lightened.[16][17]

The first revised aircraft, designated YF-102A flew on 20 December 1954, 118 days after the redesign started, exceeding Mach 1 the next day.[17] The revised design demonstrated a speed of Mach 1.22 and a ceiling of 53,000 ft (16,154 m). These improvements were sufficient for the Air Force to allow production of the F-102, with a new production contract signed in March 1954.[18]

800px-Convair_YF-102A_on_ramp_E-2551.jpg

I never was able to reach Mach 1 with my tri either even with the 'Coke Bottle' hull/keel root... 20 knots was about all I could ever do and then a big sucky wake would prevent the boat from sailing any faster. Probably a good thing because without a shaft lock, the torque on the solid prop would overcome the compression of the little Yanmar and start the engine! If you had the shift in reverse the motor would start running backwards and fill the cabin with exhaust. I do praise Cross for his implementation of some of his aero theories on the vented wing decks and upside down crossbeam foil cambers for 'ground effect' and even proved it by being the only multihull in Hurricane Hugo in Culebra Bahia Honda to not flip during that exciting night. As soon as phone service was restored after the storm I called Norm to tell him how the big tri would liftoff and then stall about the time the transom would get pushed under preventing the boat from flipping backwards in the nearly 200 knot gusts. I was saddened to have his widow answer the phone and tell me that Norm had just recently passed but thanked me for my sharing the experience. Norm must have been my angel that terrible night.

I knocked that silly keel off after about 10 years in the Caribbean and built a proper daggerboard for it, ala Newick.

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Need more practical stuff, sorry! I sail.

I can relate, but if I'm going to sail stuff I can't buy off the shelf, or have designed and built built for me (:) it's only $$$$$$!!!!!!:)), I wind up doing it myself, and this sort of stuff becomes part of the practical equation. Believe me, sometimes an RS Aero starts looking really really good, what with the ongoing progression of my biochemistry's sensitization to adhesive and wood products.

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Need more practical stuff, sorry! I sail.

I can relate, but if I'm going to sail stuff I can't buy off the shelf, or have designed and built built for me ( :) it's only $$$$$$!!!!!! :)), I wind up doing it myself, and this sort of stuff becomes part of the practical equation. Believe me, sometimes an RS Aero starts looking really really good, what with the ongoing progression of my biochemistry's sensitization to adhesive and wood products.

 

Telling you Amati. Get the F27 tri and come play with us. You can take off beams and floats and try new ones (with just a few turns of a wrench) to your heart's delight and if none of the proa experiments work you still have a fun trimaran to sail. No biochemistry involved! Just fast fun sailing!! :)

 

PS - and if you come up w a faster F27 proa version we will all follow your lead!!

 

PPS - I am just lurking these days and following along now that all the angry folks seem to have left.

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The tri in my life is an L7, and I can't figure out how to keep the mast up with a slack shroud. Long spar? (Although she's a slider, so at least that part would be easier. ;)

 

I suppose if we heeled the monomaran (Amati- she's skinny, so the Dragonfly crowd crowned her a monomaran. It's a long story...) over 90 degrees so the 8.5' keel was parallel to the water....

 

She's got a bulb keel, so that might work as a visual aid-

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Vacanti is a retired Boeing fluid flow guru, and did the calcs for the keel on Amati (which works great). So any assertions on my part viz the supersonic analogy, even based on criticisms I've come across of the software, are without a doubt very superficial! :) Norwood wasn't a lightweight either, so it's difficult to reject what look like non intuitive results out of hand. Lowrider Moth hulls, or the Serenity Windsurfer hulls seem to point in the same direction, and resulted in my own full size experiment. I have a YouTube of my canoe sailing if you'd like, but if I go off SA and link it, I'll get kicked off so I can't edit it back into this post. Let me know...

 

The calcs I've been looking are in displacement mode and the results are expressed in wave drag in pounds. Only certain shapes give wave drag in pounds going back to zero. If you're interested, you can download a trial sample of the software off the web for free. I don't remember if that gives wave and friction drag, but if you're interested, Google Vacanti Yacht Design Software.

You've probably heard the expression "Extraordinary claims demand extraordinary proof."

 

It would be pretty extraordinary if someone could design a hull with zero wave drag at its hull speed.

 

What's the extraordinary proof? That the code developer used to work at Boeing? That your boat could sail with a keel that he designed? That you built a cool boat?

 

I don't think so!

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The tri in my life is an L7, and I can't figure out how to keep the mast up with a slack shroud.

 

Yea the F27 would have a better chance than the L7 to be able to keep its original rig up with the original sail plan even in Atlantic mode where it would be without the cap shrouds. Easy in Pacific mode obviously.

 

You got a heck of a collection there, LOL.

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Vacanti is a retired Boeing fluid flow guru, and did the calcs for the keel on Amati (which works great). So any assertions on my part viz the supersonic analogy, even based on criticisms I've come across of the software, are without a doubt very superficial! :) Norwood wasn't a lightweight either, so it's difficult to reject what look like non intuitive results out of hand. Lowrider Moth hulls, or the Serenity Windsurfer hulls seem to point in the same direction, and resulted in my own full size experiment. I have a YouTube of my canoe sailing if you'd like, but if I go off SA and link it, I'll get kicked off so I can't edit it back into this post. Let me know...

The calcs I've been looking are in displacement mode and the results are expressed in wave drag in pounds. Only certain shapes give wave drag in pounds going back to zero. If you're interested, you can download a trial sample of the software off the web for free. I don't remember if that gives wave and friction drag, but if you're interested, Google Vacanti Yacht Design Software.

What is your YouTube name and the video tittle?

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Vacanti is a retired Boeing fluid flow guru, and did the calcs for the keel on Amati (which works great). So any assertions on my part viz the supersonic analogy, even based on criticisms I've come across of the software, are without a doubt very superficial! :) Norwood wasn't a lightweight either, so it's difficult to reject what look like non intuitive results out of hand. Lowrider Moth hulls, or the Serenity Windsurfer hulls seem to point in the same direction, and resulted in my own full size experiment. I have a YouTube of my canoe sailing if you'd like, but if I go off SA and link it, I'll get kicked off so I can't edit it back into this post. Let me know...

 

The calcs I've been looking are in displacement mode and the results are expressed in wave drag in pounds. Only certain shapes give wave drag in pounds going back to zero. If you're interested, you can download a trial sample of the software off the web for free. I don't remember if that gives wave and friction drag, but if you're interested, Google Vacanti Yacht Design Software.

You've probably heard the expression "Extraordinary claims demand extraordinary proof."

 

It would be pretty extraordinary if someone could design a hull with zero wave drag at its hull speed.

 

What's the extraordinary proof? That the code developer used to work at Boeing? That your boat could sail with a keel that he designed? That you built a cool boat?

 

I don't think so!

Well, got to start somewhere.

 

Should all cellists play Strads?

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Vacanti is a retired Boeing fluid flow guru, and did the calcs for the keel on Amati (which works great). So any assertions on my part viz the supersonic analogy, even based on criticisms I've come across of the software, are without a doubt very superficial! :) Norwood wasn't a lightweight either, so it's difficult to reject what look like non intuitive results out of hand. Lowrider Moth hulls, or the Serenity Windsurfer hulls seem to point in the same direction, and resulted in my own full size experiment. I have a YouTube of my canoe sailing if you'd like, but if I go off SA and link it, I'll get kicked off so I can't edit it back into this post. Let me know...

The calcs I've been looking are in displacement mode and the results are expressed in wave drag in pounds. Only certain shapes give wave drag in pounds going back to zero. If you're interested, you can download a trial sample of the software off the web for free. I don't remember if that gives wave and friction drag, but if you're interested, Google Vacanti Yacht Design Software.

What is your YouTube name and the video tittle?

https://m.youtube.com/watch?v=Q4yF6M7SfZk

 

Vacanti is a retired Boeing fluid flow guru, and did the calcs for the keel on Amati (which works great). So any assertions on my part viz the supersonic analogy, even based on criticisms I've come across of the software, are without a doubt very superficial! :) Norwood wasn't a lightweight either, so it's difficult to reject what look like non intuitive results out of hand. Lowrider Moth hulls, or the Serenity Windsurfer hulls seem to point in the same direction, and resulted in my own full size experiment. I have a YouTube of my canoe sailing if you'd like, but if I go off SA and link it, I'll get kicked off so I can't edit it back into this post. Let me know...

The calcs I've been looking are in displacement mode and the results are expressed in wave drag in pounds. Only certain shapes give wave drag in pounds going back to zero. If you're interested, you can download a trial sample of the software off the web for free. I don't remember if that gives wave and friction drag, but if you're interested, Google Vacanti Yacht Design Software.

What is your YouTube name and the video tittle?

https://m.youtube.com/watch?v=Q4yF6M7SfZk

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Not replying to Tink's ? https://en.wikipedia.org/wiki/Cheers_(proa) "Cheers" nothin' special except kewl; but I like it more if a tacker.

? Have you got the Cheers book, and back in print, someone must believe in Proas,

IMHO a tacker only works as a day boat. If a tacker when an Atlantic proa you are trying to left the main hull, as Pacific proa you are trying to lift the outrigger, RM is much less so sail area has to be less.

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Vacanti is a retired Boeing fluid flow guru, and did the calcs for the keel on Amati (which works great). So any assertions on my part viz the supersonic analogy, even based on criticisms I've come across of the software, are without a doubt very superficial! :) Norwood wasn't a lightweight either, so it's difficult to reject what look like non intuitive results out of hand. Lowrider Moth hulls, or the Serenity Windsurfer hulls seem to point in the same direction, and resulted in my own full size experiment. I have a YouTube of my canoe sailing if you'd like, but if I go off SA and link it, I'll get kicked off so I can't edit it back into this post. Let me know...

The calcs I've been looking are in displacement mode and the results are expressed in wave drag in pounds. Only certain shapes give wave drag in pounds going back to zero. If you're interested, you can download a trial sample of the software off the web for free. I don't remember if that gives wave and friction drag, but if you're interested, Google Vacanti Yacht Design Software.

What is your YouTube name and the video tittle?
https://m.youtube.com/watch?v=Q4yF6M7SfZk

 

Vacanti is a retired Boeing fluid flow guru, and did the calcs for the keel on Amati (which works great). So any assertions on my part viz the supersonic analogy, even based on criticisms I've come across of the software, are without a doubt very superficial! :) Norwood wasn't a lightweight either, so it's difficult to reject what look like non intuitive results out of hand. Lowrider Moth hulls, or the Serenity Windsurfer hulls seem to point in the same direction, and resulted in my own full size experiment. I have a YouTube of my canoe sailing if you'd like, but if I go off SA and link it, I'll get kicked off so I can't edit it back into this post. Let me know...

The calcs I've been looking are in displacement mode and the results are expressed in wave drag in pounds. Only certain shapes give wave drag in pounds going back to zero. If you're interested, you can download a trial sample of the software off the web for free. I don't remember if that gives wave and friction drag, but if you're interested, Google Vacanti Yacht Design Software.

What is your YouTube name and the video tittle?
https://m.youtube.com/watch?v=Q4yF6M7SfZk

Big thanks, wifi here won't play. Back home tomorrow so will look then

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My Cross 42R trimaran had a funky 'constant section area' themed hull/keel that was a carryover from Norm's time an Conair or Convair as an aeronautical engineer. That was what led to the 'wasp waisted' fuselages of which the F-102 was probably the best example. The 'area rule' which led to that feature apparently only works in a compressible medium (air) and didn't help drag or wave generation at the air/water interface.

 

Quote from Wiki on the F 102

 

To solve the problem and save the F-102, Convair embarked on a major redesign, incorporating the recently discovered area rule, while at the same time simplifying production and maintenance.[15] The redesign entailed lengthening the fuselage by 11 ft (3.35 m), being "pinched" at the midsection (dubbed the "Coke Bottle configuration"), with two large fairings on either side of the engine nozzle, with revised intakes and a new, narrower canopy. A more powerful model of the J57 was fitted, and the aircraft structure was lightened.[16][17]

The first revised aircraft, designated YF-102A flew on 20 December 1954, 118 days after the redesign started, exceeding Mach 1 the next day.[17] The revised design demonstrated a speed of Mach 1.22 and a ceiling of 53,000 ft (16,154 m). These improvements were sufficient for the Air Force to allow production of the F-102, with a new production contract signed in March 1954.[18]

 

800px-Convair_YF-102A_on_ramp_E-2551.jpg

 

I never was able to reach Mach 1 with my tri either even with the 'Coke Bottle' hull/keel root... 20 knots was about all I could ever do and then a big sucky wake would prevent the boat from sailing any faster. Probably a good thing because without a shaft lock, the torque on the solid prop would overcome the compression of the little Yanmar and start the engine! If you had the shift in reverse the motor would start running backwards and fill the cabin with exhaust. I do praise Cross for his implementation of some of his aero theories on the vented wing decks and upside down crossbeam foil cambers for 'ground effect' and even proved it by being the only multihull in Hurricane Hugo in Culebra Bahia Honda to not flip during that exciting night. As soon as phone service was restored after the storm I called Norm to tell him how the big tri would liftoff and then stall about the time the transom would get pushed under preventing the boat from flipping backwards in the nearly 200 knot gusts. I was saddened to have his widow answer the phone and tell me that Norm had just recently passed but thanked me for my sharing the experience. Norm must have been my angel that terrible night.

 

I knocked that silly keel off after about 10 years in the Caribbean and built a proper daggerboard for it, ala Newick.

Wasn't part of the argument for the area rule on the hull that the gravity interface was sucked down without it, and the coke bottle indentation kept the flow flatter? Can you lump NS14 recent design practice in with this?

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I do praise Cross for his implementation of some of his aero theories on the vented wing decks and upside down crossbeam foil cambers for 'ground effect' and even proved it by being the only multihull in Hurricane Hugo in Culebra Bahia Honda to not flip during that exciting night. As soon as phone service was restored after the storm I called Norm to tell him how the big tri would liftoff and then stall about the time the transom would get pushed under preventing the boat from flipping backwards in the nearly 200 knot gusts. I was saddened to have his widow answer the phone and tell me that Norm had just recently passed but thanked me for my sharing the experience. Norm must have been my angel that terrible night.

I knocked that silly keel off after about 10 years in the Caribbean and built a proper daggerboard for it, ala Newick.

Holy shit! I want to know more about this experience. It's pretty obvious that you were aboard. I went through two 100 knot hurricanes in St Croix and that was terrifying even though I was in a very protected spot, but Hugo was a whole different animal. Any long term emotional scars, nightmares, or flashbacks? Elaborate!

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Hi Russ,

 

I could write a book about that night. Jack Petith did about his experience in Salt River on St Croix. I think the title was 'The Night the Boats Flew'. He gave me a manuscript to read well before he got i published. I think it came out in French first but should be available in English now. Have you heard Terry Merrigans account of his double flip in Salt River on his tri? He was upside down and then got flipped a second time if I remember correctly. His mast was stuck in the mud after the first flip and when he got picked up by the wind the second time the mast and the deck halyard turning blocks ripped half the cabin top off. He crawled up into the tiny single berth fwd and then heard and felt something come crashing across his boat. That turned out to be the 60' Hugo ************ cat Varoa Kane flipping several times in succession across the supposedly best hurricane hole in the Caribbean, Salt River. People used to argue which was the better hurricane hole, Salt River or Bahia Honda in Culebra where I was for Hugo but both got totally hammered that ill fated night.

 

There were two crew on Varoa Kane holed up in the tiny centerline deckhouse on what was basically an open bridgedeck cat and the little pod came completely loose from the rest of the cat as it self destructed on its way far into the mangroves. Almost like an escape pod but they were pretty beat up when they came to rest not far from Terry's boat. He had turned on a light in his tiny refuge and was pretty close to wigging out and the other guys saw the light shining from his foredeck hatch. They crawled through the wind and muck of the mangroves towards the light and were clawing at the hatch when Terry looked up and saw what he was sure were wounded and blood stained Zombies which was pretty close to the the truth at that point. He finally came to his senses and opened the hatch and let them in to the tiny shelter that a Newick 36 forepeak offers. I hope I got most of this close to the truth and maybe Terry will chime in but I'll start a separate thread on the Hugo event and hope others that were there can join in.

 

I actually had a pretty mellow night in Culebra that night until the eye passed over at first light and then all hell broke loose. My girlfriend and I managed to conceive our first child that night and I'm convinced that the extreme low atmospheric pressure that night sucked a viable egg right out of what had been a unproductive womb. Maybe it was the adrenaline that got the juices flowing! Don't ever let a girl tell you that she can not get pregnant...

 

Scars? Hell yeah!

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It would be pretty extraordinary if someone could design a hull with zero wave drag at its hull speed.

 

 

Since the very concept of hull speed is all about wave drag, zero wave drag implies no hull speed (or perhaps infinite hull speed).

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All you Farrier boys can still fold and have a proa

 

 

 

post-62633-0-30501300-1492852515_thumb.jpg

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Very interesting. Not simple...take the idea to its extremes, you want to find out its viability, which I can tell you from experience. Instant case, did project goes as planned? What happens later, and so on? But, nice rig.

 

No I do not have "Cheers" book but will look for it. Also, I know a few spots where shunting is not possible and why I constructed a tacker like Whites and the Malibu Outrigger. I just think the more universal an application, the more useful it will prove to be. Besides, it works, simply. But, that is just me. Not trying to proselytize. If it works simply in the strategic sense, I will usually give it a shot, if I can.

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Very interesting. Not simple...take the idea to its extremes, you want to find out its viability, which I can tell you from experience. Instant case, did project goes as planned? What happens later, and so on? But, nice rig.

 

No I do not have "Cheers" book but will look for it. Also, I know a few spots where shunting is not possible and why I constructed a tacker like Whites and the Malibu Outrigger. I just think the more universal an application, the more useful it will prove to be. Besides, it works, simply. But, that is just me. Not trying to proselytize. If it works simply in the strategic sense, I will usually give it a shot, if I can.

I don't think it would be too hard to get the best of both worlds. Let's say a Pacific Proa when there is sea room and tacker in tight spots

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Very interesting. Not simple...take the idea to its extremes, you want to find out its viability, which I can tell you from experience. Instant case, did project goes as planned? What happens later, and so on? But, nice rig.

 

No I do not have "Cheers" book but will look for it. Also, I know a few spots where shunting is not possible and why I constructed a tacker like Whites and the Malibu Outrigger. I just think the more universal an application, the more useful it will prove to be. Besides, it works, simply. But, that is just me. Not trying to proselytize. If it works simply in the strategic sense, I will usually give it a shot, if I can.

I don't think it would be too hard to get the best of both worlds. Let's say a Pacific Proa when there is sea room and tacker in tight spots

 

Tink, Not to disagree, but the combo is not simple or simpler, if you get my drift.

 

I thought of that, but use of scrapped hulls with "bow" and "stern" precluded doing it, and the idea of shunting in on particular place was very disconcerting, so I went with what I have been doing for decades...tacking rig.

 

One sail; one tiller, lay it over and that is it, bow moves or stern and sail follows...what could be simpler?

 

One sunny summer day long ago, I was out cruising in my 110 keel boat with a couple friends. We decided to enter a popular area off Big Island, a popular Minnetonka spot west of Mpls. We were under jib and main, reach, heading toward shore. For some reason my attention was not on course, likely setting beer on floor)...When I looked up, not 10 meters in front was a huge cruiser...broadside...anchored.

 

Well, Capt. Bob, acting cool as can be, pushed the tiller over to port and, as we tacked and sailed by, not 4 feet from the cruiser, exchanged smiles and hellos with the cruiser's crew, like I planned the whole thing. (I must admit, it did appear a smooth deal.) I think they thought we were about to smash a hole dead center in the cruiser...as our VMG was high, very high and heeled.

 

If a shunter, no way to avoid crunch...that I can visualize.

 

I have another tale also of sailing through a jetty channel into a slip, not possible with a shunter.

 

But, in truth, the course should be determined by the rig's limits, and we were pushing it then.

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It would be pretty extraordinary if someone could design a hull with zero wave drag at its hull speed.

Since the very concept of hull speed is all about wave drag, zero wave drag implies no hull speed (or perhaps infinite hull speed).

 

Exactly!

 

Instead of "extraordinary," maybe I should have said "impossible", "absurd", or something stronger. But I don't think Amati wants to hear it.

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It would be pretty extraordinary if someone could design a hull with zero wave drag at its hull speed.

Since the very concept of hull speed is all about wave drag, zero wave drag implies no hull speed (or perhaps infinite hull speed).

 

Exactly!

 

Instead of "extraordinary," maybe I should have said "impossible", "absurd", or something stronger. But I don't think Amati wants to hear it.

 

Or, no hull...

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Swang...merci...boat porn...wet dreams for me...all over it!

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It would be pretty extraordinary if someone could design a hull with zero wave drag at its hull speed.

Since the very concept of hull speed is all about wave drag, zero wave drag implies no hull speed (or perhaps infinite hull speed).

Exactly!

 

Instead of "extraordinary," maybe I should have said "impossible", "absurd", or something stronger. But I don't think Amati wants to hear it.

I do want to hear it. But FWIW I was one of those unfortunates who couldn't replicate the Millikan Oil Drop experiment and paid for it. So when I say, as I did, that models are an opinion, I actually meant it. Granted, my argument was an appeal to authority, while yours seems to be 'it's just a pile of shit.' Which is basically what self appointed enforcers were doing with the Oil Drop Experiment.

 

Resistance isn't all wave related. I think skin friction is resistance too?

 

Am I wrong in thinking that waves are a result of a hull (in this case) displacing water at a speed? And waves exist because of the gravity interface between water and the atmosphere?

 

Different hull shapes create diffferent waves, and different resistance- if that is the case, it seems a little arrogant to proclaim a truth that something is true based only on supposition. Hypersonic flow does exist. Large Boats do plane

 

I think your assertion is a very practical one based on current knowledge. But if I was willing to actually build a model, and try it out based on what I have at hand, other that your impatience with my apparent stupidity, why the condescension? I'm not denying physics- I'm trying to understand physics in a more personal way.

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It would be pretty extraordinary if someone could design a hull with zero wave drag at its hull speed.

Since the very concept of hull speed is all about wave drag, zero wave drag implies no hull speed (or perhaps infinite hull speed).

 

Exactly!

 

Instead of "extraordinary," maybe I should have said "impossible", "absurd", or something stronger. But I don't think Amati wants to hear it.

 

I do want to hear it. But FWIW I was one of those unfortunates who couldn't replicate the Millikan Oil Drop experiment and paid for it. So when I say, as I did, that models are an opinion, I actually meant it. Granted, my argument was an appeal to authority, while yours seems to be 'it's just a pile of shit.' Which is basically what self appointed enforcers were doing with the Oil Drop Experiment.

 

Resistance isn't all wave related. I think skin friction is resistance too?

 

Am I wrong in thinking that waves are a result of a hull (in this case) displacing water at a speed? And waves exist because of the gravity interface between water and the atmosphere?

 

Different hull shapes create diffferent waves, and different resistance- if that is the case, it seems a little arrogant to proclaim a truth that something is true based only on supposition. Hypersonic flow does exist. Large Boats do plane

 

I think your assertion is a very practical one based on current knowledge. But if I was willing to actually build a model, and try it out based on what I have at hand, other that your impatience with my apparent stupidity, why the condescension? I'm not denying physics- I'm trying to understand physics in a more personal way.

 

I'm sorry if I came across as arrogant & condescending. I only intended to point out a couple of matters that I thought were well-established (not my personal suppositions).

 

In any case, we shouldn't let that distract from the more interesting questions concerning proas, and I hope your experiments will help shed some light on them.

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I tried to edit 'suppositions' out, but my edit time had elapsed. What I meant to say revolves around what my theoretical physics prof told me: you understand something until you don't. Kind of zen, that.

 

He told me that when he called to apologize about the grade he gave me when the Oil Drop Experiment dirt came out, which he didn't have to do.

 

Didn't mean to get edgy, I truly respect what you've done. There a reason I dropped out of physics.

 

The poetry of the sphere. So no worries?

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Here's a link to dinghy design, take it with a pinch of salt, and scroll down to 'planing flat'

 

https://www.google.com/amp/s/sailcraftblog.wordpress.com/2016/11/23/pt-2-2-shapes-in-the-liquid-the-hull-of-todays-performance-dinghy/amp/

 

Most interesting-thanks!!

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Hi Russ,

 

I could write a book about that night. Jack Petith did about his experience in Salt River on St Croix. I think the title was 'The Night the Boats Flew'. He gave me a manuscript to read well before he got i published. I think it came out in French first but should be available in English now. Have you heard Terry Merrigans account of his double flip in Salt River on his tri? He was upside down and then got flipped a second time if I remember correctly. His mast was stuck in the mud after the first flip and when he got picked up by the wind the second time the mast and the deck halyard turning blocks ripped half the cabin top off. He crawled up into the tiny single berth fwd and then heard and felt something come crashing across his boat. That turned out to be the 60' Hugo ************ cat Varoa Kane flipping several times in succession across the supposedly best hurricane hole in the Caribbean, Salt River. People used to argue which was the better hurricane hole, Salt River or Bahia Honda in Culebra where I was for Hugo but both got totally hammered that ill fated night.

 

There were two crew on Varoa Kane holed up in the tiny centerline deckhouse on what was basically an open bridgedeck cat and the little pod came completely loose from the rest of the cat as it self destructed on its way far into the mangroves. Almost like an escape pod but they were pretty beat up when they came to rest not far from Terry's boat. He had turned on a light in his tiny refuge and was pretty close to wigging out and the other guys saw the light shining from his foredeck hatch. They crawled through the wind and muck of the mangroves towards the light and were clawing at the hatch when Terry looked up and saw what he was sure were wounded and blood stained Zombies which was pretty close to the the truth at that point. He finally came to his senses and opened the hatch and let them in to the tiny shelter that a Newick 36 forepeak offers. I hope I got most of this close to the truth and maybe Terry will chime in but I'll start a separate thread on the Hugo event and hope others that were there can join in.

 

I actually had a pretty mellow night in Culebra that night until the eye passed over at first light and then all hell broke loose. My girlfriend and I managed to conceive our first child that night and I'm convinced that the extreme low atmospheric pressure that night sucked a viable egg right out of what had been a unproductive womb. Maybe it was the adrenaline that got the juices flowing! Don't ever let a girl tell you that she can not get pregnant...

 

Scars? Hell yeah!

 

Hi Rasputin,

Are you going to start a thread about this? I'd like to know what has been published. I did hear Terry Merrigan's story, but not from him. My father told me the story, which makes me doubt some of the details. Is it true that his Newick tri was flying like a kite on the anchor line, upside down with the mast acting like a tail before it cartwheeled across the bay? Maybe not, but the bloody hands scratching on the hatch could be fact.

It sounds like your experiences were slightly different, but still produced some lasting effects.

The Caribbean kind of spit me out before Hugo, which may have been a blessing but I'll never know what 200 knots of wind feels like

What are you doing now? I know that you are doing some CAD work, but that's all I know.

I'm getting ready for attempting the R2AK on my G-32. The race is coming right up and I haven't sailed the boat since last fall. It has a new rig now, but have been waiting on the sails for a long time. There has been plenty to do though. The electrical system and the pedal drive system are happening now. Pelagic autopilots as sponsored me with an autopilot and it just arrived. Looks really cool. Sort of aeronautical, industrial looking. Nothing like a Raymarine pilot.

 

If you compile some Hugo stories (including your own), please let me know. By the way, I had lunch with Norman Cross in a tittie bar. Okay, I was only 10 or 11 and I was with my parents, but I remember Norman and I remember the titties.

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One sunny summer day long ago, I was out cruising in my 110 keel boat with a couple friends. We decided to enter a popular area off Big Island, a popular Minnetonka spot west of Mpls. We were under jib and main, reach, heading toward shore. For some reason my attention was not on course, likely setting beer on floor)...When I looked up, not 10 meters in front was a huge cruiser...broadside...anchored.

 

Well, Capt. Bob, acting cool as can be, pushed the tiller over to port and, as we tacked and sailed by, not 4 feet from the cruiser, exchanged smiles and hellos with the cruiser's crew, like I planned the whole thing. (I must admit, it did appear a smooth deal.) I think they thought we were about to smash a hole dead center in the cruiser...as our VMG was high, very high and heeled.

 

 

You have obviously not shunted on a boat set up to do it properly. Dump the sheet, pull in the new one and the boat stops in less than it's own length. The rudders rotate automatically and you are sailing in the other direction. Whether you could do this in 10m at high speed is a moot point, but you could certainly luff head to wind, then sail off in the opposite direction. Again, if the proa is set up properly.

 

The following was written by an experienced beach cat sailor:

"I watched Rob shunt his 7.5m/25' proa upwind up the narrow (35m/115' wide for most of it) boat filled channel in front of his house so fast and easy I thought he must've had an electric motor hidden in the leeward hull. I would've had a very difficult time doing it in a beach cat without stalling, hitting somebody's boat and/or breaking out a canoe paddle.

With the exception of a wind surfer, I had never seen a sailboat with a reverse gear before. He could head right for something, then throw it in reverse, back away and bolt off in a new direction under perfect control."

 

Shunting really comes into it's own in a man overboard scenario. Drop the sheet, trim the new sheet and sail straight back to the mob and stop directly on top of him. No tacking/gybing and circling, no flogging sails and sheets and little leeway when stopped.

 

it is also far safer in a blow. Instead of the white knuckle surf down a wave and gybe at the bottom with the main crashing across and into the shrouds, you come up onto a reach, dump the sheet, trim the new one and off you go. Upwind, it is also safer as you do not need to have enough sail up to force the boat through the eye of the wind. So, just enough sail to keep the boat moving and none of the worries about getting caught in irons, drifting backwards onto the rudders, backing headsails, etc.

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Here's a link to dinghy design, take it with a pinch of salt, and scroll down to 'planing flat'

 

https://www.google.com/amp/s/sailcraftblog.wordpress.com/2016/11/23/pt-2-2-shapes-in-the-liquid-the-hull-of-todays-performance-dinghy/amp/

Scow shape...always have been around showing their stuff in one form or another, right, from sea mammals to boats, in the long term.

 

The Flying Dutchman is one wakeless hull form at any velocity...am thinkin'

post-38311-0-65973000-1492936934_thumb.jpg

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One sunny summer day long ago, I was out cruising in my 110 keel boat with a couple friends. We decided to enter a popular area off Big Island, a popular Minnetonka spot west of Mpls. We were under jib and main, reach, heading toward shore. For some reason my attention was not on course, likely setting beer on floor)...When I looked up, not 10 meters in front was a huge cruiser...broadside...anchored.

 

Well, Capt. Bob, acting cool as can be, pushed the tiller over to port and, as we tacked and sailed by, not 4 feet from the cruiser, exchanged smiles and hellos with the cruiser's crew, like I planned the whole thing. (I must admit, it did appear a smooth deal.) I think they thought we were about to smash a hole dead center in the cruiser...as our VMG was high, very high and heeled.

 

 

You have obviously not shunted on a boat set up to do it properly. Dump the sheet, pull in the new one and the boat stops in less than it's own length. The rudders rotate automatically and you are sailing in the other direction. Whether you could do this in 10m at high speed is a moot point, but you could certainly luff head to wind, then sail off in the opposite direction. Again, if the proa is set up properly.

 

The following was written by an experienced beach cat sailor:

"I watched Rob shunt his 7.5m/25' proa upwind up the narrow (35m/115' wide for most of it) boat filled channel in front of his house so fast and easy I thought he must've had an electric motor hidden in the leeward hull. I would've had a very difficult time doing it in a beach cat without stalling, hitting somebody's boat and/or breaking out a canoe paddle.

With the exception of a wind surfer, I had never seen a sailboat with a reverse gear before. He could head right for something, then throw it in reverse, back away and bolt off in a new direction under perfect control."

 

Shunting really comes into it's own in a man overboard scenario. Drop the sheet, trim the new sheet and sail straight back to the mob and stop directly on top of him. No tacking/gybing and circling, no flogging sails and sheets and little leeway when stopped.

 

it is also far safer in a blow. Instead of the white knuckle surf down a wave and gybe at the bottom with the main crashing across and into the shrouds, you come up onto a reach, dump the sheet, trim the new one and off you go. Upwind, it is also safer as you do not need to have enough sail up to force the boat through the eye of the wind. So, just enough sail to keep the boat moving and none of the worries about getting caught in irons, drifting backwards onto the rudders, backing headsails, etc.

 

Have little doubt, what you say is true, but I honestly do not think the crunch would have been avoided as a shunter, not enough room...and the whole maneuver was so slick, it seemed casual-planned...but in truth tillerman's panic-ville, especially at what might have happened. I guess I might think differently, had I been shunting since I was 12, but tacking got sort of ingrained somewhere. I would love to sailed a shunter...like Cheers and learn.

 

BTW, FWIW, Cheers and scow idea have me rethinking the foam aka shape...all things work out in time.

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Typo, meant to write "ama" shape above...

 

"If.I.am.allowed" from far above posting, may be the most significant phrase in this thread, IMHO. I missed it earlier. (Vantage 4/18)

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Apologies for the drift but I think Petith's book , 'Heart of the Storm, the night the boats flew' is extraordinary. Not only is it an account

of Hugo but also of his (class III) win in the 84 OSTAR in his 38' Newick trimaran. Jack

has the gift of writing, no doubt about that. Easy to find the download. Cheers.

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Thanks for the golden oldies video, it brought back many kind thoughts. It seems that boats were finer then and didn't want to kill you with power.

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Thanks for the golden oldies video, it brought back many kind thoughts. It seems that boats were finer then and didn't want to kill you with power.

+1

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I keep forgetting to ask.

 

Anyone have experience making a foam ama? If so could use your advice.

 

Am planning on making new ama with pick foam, and hot wire to shape-using train transformer...and then glassing with two layers of 6oz glass. ...

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I keep forgetting to ask.

 

Anyone have experience making a foam ama? If so could use your advice.

 

Am planning on making new ama with pick foam, and hot wire to shape-using train transformer...and then glassing with two layers of 6oz glass. ...

http://www.swaylocks.com/forums/hot-wire-shaping-and-foam-lock-adhesive

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Amati, much thanks.

 

Perusing the site.

 

One thing occurred to me as I was noting the clever doings: Boards are thin compared to outrigger hulls.

 

I have been trying to avoid using longboard or sander...foam is messy...and latched to hot wire.

 

Even thought of making a sort of hot wire die and pushing hull though it, but the rocker shape will still need shaping...may still use.

 

Still very interesting material and am already changing some scheduling and setting up to use the edges of ply deck and stem, as guide-ways to move wire along hull sides, after I epoxy the foam to the shear-web. Trick will be the shape from end views, especially near bow and stern. Fun....

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Are you using xps and plywood? If you are, using a pull saw, sureform , 30 and 60 grit, you can get it shaped in a couple of hours. It's easy and fun.

 

Leave the laminating surfaces rough (30 to 60 grit) to created more bonding area. Sand off the shiny surfaces. In hot weather, foam outgassing can pop the glass off the xps, so you need all the grip you can get. For bonding plywood to xps, use Gorilla Glue. It also has health issues so read the safety sheet. I like the white GG- it's faster, and cures softer, so when you're shaping, it doesn't tear up the foam as much as the brown stuff.

 

Epoxy is heavy.

 

Sanding or melting xps will release harmful gasses, so make sure you're really well ventilated. Find and use appropriate mask and filter.

 

If you have a dog, they like to eat any kind of foam. This includes GG. This will not end well.

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Ply....cheapo 1/8 Akuma ? for deck and same for keel but with Bannister ripped and then fastened to the play with filler on edges, for keel or stem.

 

I tend to use what I have on hand and make it work. Project is 4 years running. I do not need new outrigger hull, but like to build and have urge to try.

 

I know epoxy is heavier than most, and am looking in to the glue on that site. Still, have gallon or so of Epoxy here and some cabo, so may mix goo and glue...next week.

 

The shear web is 1/8 same ply from local box...small town.

 

I have to determine distance to aka from deck/web-top and set the stanchions for the straps and the aluminum fastener thingy inside of tube. Tricky deal that.

 

I use the pink stuff cause I can get it, epoxy works with it and cheap.

 

Did not know about the vapor...very good advice. My basset died few years back and have not got what it takes to go through that again.

 

Will have to figure out the vapor thing...BTW, Gorilla glue is water base, ana-oxygen glue...and spendy. Might have to go with epoxy and cabo glue and live with the weight.

 

Appreciate the assistance...fun!

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You might try my lazy mold outrigger build. Get a free H16, or Prindle 16 hull. invert it, lay Baltek or Ariex in the sheer, spile the bottom,which is now the top. Glass with6oz and epoxy. Repeat with other plug, join butt to butt, deck using the open hull as a sag mold {another story}. If you are hyper like me it only takes a couple of days, and if the the two plugs are close, you will have a lovely out rigger, with no shaping or dust. Good luck.

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You might try my lazy mold outrigger build. Get a free H16, or Prindle 16 hull. invert it, lay Baltek or Ariex in the sheer, spile the bottom,which is now the top. Glass with6oz and epoxy. Repeat with other plug, join butt to butt, deck using the open hull as a sag mold {another story}. If you are hyper like me it only takes a couple of days, and if the the two plugs are close, you will have a lovely out rigger, with no shaping or dust. Good luck.

Very trick!

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Ply....cheapo 1/8 Akuma ? for deck and same for keel but with Bannister ripped and then fastened to the play with filler on edges, for keel or stem.

 

I tend to use what I have on hand and make it work. Project is 4 years running. I do not need new outrigger hull, but like to build and have urge to try.

 

I know epoxy is heavier than most, and am looking in to the glue on that site. Still, have gallon or so of Epoxy here and some cabo, so may mix goo and glue...next week.

 

The shear web is 1/8 same ply from local box...small town.

 

I have to determine distance to aka from deck/web-top and set the stanchions for the straps and the aluminum fastener thingy inside of tube. Tricky deal that.

 

I use the pink stuff cause I can get it, epoxy works with it and cheap.

 

Did not know about the vapor...very good advice. My basset died few years back and have not got what it takes to go through that again.

 

Will have to figure out the vapor thing...BTW, Gorilla glue is water base, ana-oxygen glue...and spendy. Might have to go with epoxy and cabo glue and live with the weight.

 

Appreciate the assistance...fun!

I use the blue XPS- 4" thick goes a long way, with less gluing- but we live in a cold winter area so it's available in all sorts of thicknesses and densities. FWIW, I go to a local roofing supply company- they seem to have the most choice.

If the XPS is long enough- like 16', 4" will bend enough to get s decent rocker, even edge glued, like up to ~ 3-4" rocker, which makes things a lot easier and quicker.

 

I've also been experimenting with monolithic pieces of balsa, and shaping that with a 1/8" strong back of okume down the middle. Then spar varnish. More surfboard stuff..

 

Gets pricey, unless gluing strips ad nauseum appeals-

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Amati, dig that. Will ask local roofer. I messed up a bit, the web is likely to be 1/4" ply not 1/8" Akuma. The 1/8 for deck and keel only.

 

Guerdon, Also a thanks. Now, as I understand your post, you want me to take my H-16 hull and make a sort of plug...but to understand fully, can you explain "in the sheer" and "spile?" Am assuming the idea is the Airex to shape, the glass to form plug?

 

Did not know the Pink came in 16 length...was going to use the common 8'. The outrigger is only 16.

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Amati, dig that. Will ask local roofer. I messed up a bit, the web is likely to be 1/4" ply not 1/8" Akuma. The 1/8 for deck and keel only.

 

Guerdon, Also a thanks. Now, as I understand your post, you want me to take my H-16 hull and make a sort of plug...but to understand fully, can you explain "in the sheer" and "spile?" Am assuming the idea is the Airex to shape, the glass to form plug?

 

Did not know the Pink came in 16 length...was going to use the common 8'. The outrigger is only 16.

Pink and blue do not, BUT, if you join them lengthwise with a butt joint in the middle, and a 1/8" ply thingie down the middle , it works nicely.

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Amati, I checked and have to use 8 foot Owens Pink...end-to-end as planned...three layers of two-inch, staggered along shear web. Hull depth from deck to keelson only 12-inches... max; rocker to bow and stern. Will likely have to hand hot-wire to narrow foam shape to the 2-inch beam at bow and 4-inch beam at transom, from 12-inch beam amidship.

 

Nothing easy, dang it. Looks like I will use 1/8 Okuma for web, from local big-box may add stiffener strip along top to distribute stress from single chain plate forward. Glass exterior...tricky but lighter than planned, am thinking. All per orig Malibu Outrigger plans, but with rounded out rigger instead of chine version, but straight sided chine version would be easier to construct, so may end up with that. I am flexible and the difference should be negligible, maybe even asymetrical like Hobie 16 outrigger that is on boat now.

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Are you going to laminate multiple stringers between the 2" slabs of foam? There are differences of approach between using thin plywood / epoxy stringers (or even thin cedar strips / epoxy stringers), or depending on the epoxy glue joint itself as a stringer, although that seems like a leap of faith....

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Well, figured to do as Dierking suggests. Just foam on shear web...with thin ply deck and the Bannister keel for rugged hits, under some carbon and glass. Maybe 1/4 inch shear web for strength when the ama is taking it...port tack puts the pressure on larb'd ama...for me it is all new and a crap shoot, with overkill to preclude some probs...I know squat. I have thought of laying in carbon tow loa between foam chunks but worry about wasting it when hot wiring shape...I figure I have a week before I have to decide and buy stuff and begin mixing goop etc.

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... Looks like I will use 1/8 Okuma for web, from local big-box ...

When I 1st read this, I thought you were just misspelling "Okoume" & was surprised you could find it at a big-box place. But a little Googling showed me I was wrong & there actually is something called "Okuma."

Can you tell me how they compare?

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Doug, I honestly have no clue. I just went there and they have it...it is not Marine ply, but thin enough I can double if I need. It may be gone and I will have to use 1/4 stuff. I live in small town and lottsa stuff is hard to get, so I do with what is available and do lots of "doctoring."

 

BTW, Amati, I use carbon strips and tow to being up somethings that are not quite as strong as should be...and looks now like I may be stuck with 1/4 ply...for shear web...not a biggie, but needs accommodating.

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BobBill, the outside sheer of those hulls acts as a railing/support for the core. The production hull becomes the male plug for your new outrigger. Spile is the word for measure/fitting boat planks, which in this case are the core sides. If you do this build, I advise you to have someone who has done prototype fabrication walk you through it dry before you burn money. I never know who I am addressing as far as skill levels/experience.

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Guedon, Thanks. Woodsy Minnesotan uses spiles to tap Maples...I get it and thanks. Good advice! I will follow it. My best bet seems to do the Dierking schedule with foam and epoxy, working out hot wire thingy...Right now the boat up runs near 400 lbs or near 180 kilos...new outrigger will reduce by some 100 lbs or 25%. That is a lot if I do it proper. With 220 sq ft sail, might be doing some hiking...idea is to add weight to ama if needed, as opposed to present config, which I cannot lighten, though it did use scrapped Hobie cat hull.

 

If it does work, may bring to Malibu for a run for fun, with old orig MO, if any are still sailing...old wood rigs.

 

Pics being worth many words pic I happen to have on hand below gives orig ama shape see bottom of pic...main hull is rounded H-19 ama is hoped to replace H-10 with more rounded or fair version of below...

post-38311-0-85833400-1493217758_thumb.gif

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BobBill, my first boat ride was in a Malibu Otrigger. I haven't seen one in years. Try looking at Zuma Beach across from Trancas. C.L.C. Has a nice successor to the orginal. My new Salamba should also be close t the spirit of the original. If you go proa, most boats seem to be trying too hard. I just made some cf hardware today, it's bombproof , stiff as hell, beautiful in an unobtainium way, and totally un fun. I remember cutting bamboo for the Malibu spars, we are losing the fun, it's like kids sports, we played, now they compete for the parents. Play always!

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BobBill, my first boat ride was in a Malibu Otrigger. I haven't seen one in years. Try looking at Zuma Beach across from Trancas. C.L.C. Has a nice successor to the orginal. My new Salamba should also be close t the spirit of the original. If you go proa, most boats seem to be trying too hard. I just made some cf hardware today, it's bombproof , stiff as hell, beautiful in an unobtainium way, and totally un fun. I remember cutting bamboo for the Malibu spars, we are losing the fun, it's like kids sports, we played, now they compete for the parents. Play always!

Dig! And thanks. I play always. Gnarly me!

 

I have always been a MO fan and of White's Dragonfly, and this project remains a bit of a trial. Never a fan of wood CLCs and lateen sail config. No special reason maybe not corporate player, just not a fan.

 

Using MO orig plans and scrapped Hobie hulls and carbon spars to be environ friend has proven to be tedious at times as lots of custom work, as with pylons for foam ama, but the boat performs as planned but have not risked high pressure as yet. This summer, indeed, after I do foam aka.

 

It "does it," I will drag to CA.

 

I would very much like to see Salamba.

 

Above are pics of rig'; one of below is idealized plan, but below is are a couple to save the trouble. My greatest problem is not being able to rig at put-in as fast as I planned. I dry-sail it.

 

The hook/loop sail takes time to attach to spars and I had to add serious stays to help weak Hobie 18 hull construction, which I only learn later. Should have used Mr. Upchurch's Tornado hull, but another tale.

post-38311-0-79919800-1493291051_thumb.jpg

post-38311-0-12827700-1493291514_thumb.jpg

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Looks like good fun. I love the name. What do you call a guy with no arms or legs in a lake? wait for it,,,, Bob.

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I remember reading about John Pizzey a couple of decades ago, and it is well worth looking into some of his solutions... I'm not sure if he's still about, It'd be great if he could weigh in on the discussion. http://proafile.com/magazine/articles/tag/john+pizzey

 

pi_piawatha.jpg

note the reverse bow/sterns in i988!

Edited by All@Sea

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All@sea, Appreciated.

 

I will say, that the Dierking shunter and particularly the Quill tacker crab claw...semi-crab claw sails, is or was designed by Seaman for his Malibu Outrigger in the 1950s.

 

It consisted of a spar upper and boom lower, bolt rope. Unstayed for downwind efficiency and beating ease.

 

Newer version has one change...sail has less leech roach and is batten-less, loose footed, and less luff-roach with hook and loop attachment to carbon spar.

 

It was not so popular, as you will note the small lateen is used by CLC as it is easier to construct and rig, but not nearly as efficient.

 

I have copies of the original plans for this sail, partly noted on the Mechanics Illustrated pic, in above thread (blue) about building a Malibu Outrigger. The idea, of course, allows the upper spar to be far more flexible than the lower to spill air in heavy gusts and surfing before wave crests to shore, where a capsize could be quite dangerous, especially landing ashore. As I understand it, a good many stubby masts were demolished on the shoreline.

 

Below is copy of the intricate goose neck for the rig, on Seaman's boat. Has not changed. All SS, including universal block. Spendy, a bit tricky and heavy...needs to be quite strong. Newer version no different if you compare to above on Gnarly.

 

Guerdon, RE the name, you "got" some of the meaning, with "Bob," also includes the boat bobbing along in a light chop, and an unmentionable, and age. Imagination!

post-38311-0-34673000-1493369855_thumb.jpg

post-38311-0-81993400-1493370412_thumb.jpg

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Pure chance on my part. Just sort of fit, so I did it and it fits to a gooseneck...You are all over it. Very good.

 

Gonna try Amazon for the book on Newick's..Cheers ho luck so far..

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BobBill, You can get the new "Cheers" book from PT Watercraft, Russells' wife restored it as a labor of love. It was my favorite book, because it embodies fun sailing. I highly recommend it to all.

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BobBill, You can get the new "Cheers" book from PT Watercraft, Russells' wife restored it as a labor of love. It was my favorite book, because it embodies fun sailing. I highly recommend it to all.

 

+1 a great book. The account of the battle with the 'establishment' gives a great insight into one of the reasons Proas aren't as popular or developed as they should be.

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Very basic CAD sketch of a 36ft moving leeboard CRUISING proa, has far from a finished article, has some big design decisions to make yet

Tink, do you use 1/3 LOA as a rule of thumb for the longitudinal travel of your leeboard?

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Very basic CAD sketch of a 36ft moving leeboard CRUISING proa, has far from a finished article, has some big design decisions to make yet

 

Tink, do you use 1/3 LOA as a rule of thumb for the longitudinal travel of your leeboard?

Yes it was about that based on the schooner rig and a board that can pivot. To go down wing the board had to be all the way back and pivoted backwards. This shows the general (chaotic) arrangement. The red lines controlled the position of the board and I think where simplified later on.

https://youtu.be/BtOH5Ga6rvM

 

Wish I had the time, resources and place to sail so I could develop the concept more.

 

The other proa I love that is minimal and trying to be simple is Proud Mary. Simple weight steering and Gibbon rig.

 

https://youtu.be/QbPv4oL9C44 Lots of other video on YouTube

 

My first proa was weight steered with the crew 100% of the time on a trapeze, I could just walk up and down the gunwale. The rig was similar to what I have seen of yours. I lug type rig with the yard able to move fore and aft when shutting, luff becomes leach etc. I never really got enough luff tension though.

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