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      Abbreviated rules   07/28/2017

      Underdawg did an excellent job of explaining the rules.  Here's the simplified version: Don't insinuate Pedo.  Warning and or timeout for a first offense.  PermaFlick for any subsequent offenses Don't out members.  See above for penalties.  Caveat:  if you have ever used your own real name or personal information here on the forums since, like, ever - it doesn't count and you are fair game. If you see spam posts, report it to the mods.  We do not hang out in every thread 24/7 If you see any of the above, report it to the mods by hitting the Report button in the offending post.   We do not take action for foul language, off-subject content, or abusive behavior unless it escalates to persistent stalking.  There may be times that we might warn someone or flick someone for something particularly egregious.  There is no standard, we will know it when we see it.  If you continually report things that do not fall into rules #1 or 2 above, you may very well get a timeout yourself for annoying the Mods with repeated whining.  Use your best judgement. Warnings, timeouts, suspensions and flicks are arbitrary and capricious.  Deal with it.  Welcome to anarchy.   If you are a newbie, there are unwritten rules to adhere to.  They will be explained to you soon enough.  
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Amati

bi-directional Proa

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Proa, this would a fine ply sided strip plank bottom vessel.  I am not sure if you could compound curve the hulls like the early Tornado cats if you scarfed the ply amidships.   If you wanted to compare its' sections to the Tornado, you could probably get their dimensions from the association.  The early WestSystem book goes into both techniques in wonderful detail.  I have done both and they end up being about the same labor hours(the compounded hull needs a support matrix].  Another option would be to get some similar section hulls  and splice them stern to stern.  This is the fastest way, and the cheapest.  You can save an old hull set and your back at the same time.  Good luck to you.

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14 hours ago, ProaSailor said:

Yeah, strip planking is all I can think of from my limited shop experience for a round bottom.  But that isn't round without a lot of filling and fairing, which can get heavy and laborious.  I can imagine how to build a multi-chine hull, though don't have all the skills or a shop to do it, but have no idea how to achieve a compound surface of specified thickness, like this hull bottom?  3D printing might be amazing for this someday?  Print the bottom core, skin one side with fiber/epoxy, clean any print support scaffolding from the other side, then skin it with fiber/epoxy?  Builders' trade secrets.

Proa16_2017_Dec4b2.thumb.jpg.6c6a27e1cb3e4f3695be7a243337ba47.jpg

Once upon a time, long, long ago, in a land downunder, the vertical sides were done with plywood, and the round bottom was the fairest Clark style foam.  Sheathed with the finest polyester.  A bit heavy, but foam and epoxy have come a long way since then. 

That and you’d have reserve floatation.

Shaping is fun and cathartic! :)

Wear protection!

:ph34r:

(It’s not that big a big stretch for proas to become a part of the surfing/Windsurfing/paddleboard gestalt.)

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This last one of four videos sums up the details well.  Wonder how much it costs to play with those 3D printers?  Still printed parts to be assembled, not the entire hull.

 

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3 hours ago, Amati said:

Shaping is fun and cathartic! :)

I'd rather see methods that give predictable results without relying on the skills of a surfboard shaper.

I can generate CAD (CNC) for panels like these, shown at 3/16" thickness.  Allowance for material thickness on hull length and beam is minor.

I wonder if the bottom and deck could be pre-assembled (taped and finished) with vertical sleeves (tabs, bulkheads) that fit inside the topside plywood pieces?  And where you want to terminate those bottom surface strips, to finish and fair it with filler?

Proa16_2017_Dec5a.png.8a892f8f292a8d4b0fe471683ff50136.pngProa16_2017_Dec5a2.png.f1881e8593116cd398bb36199e80c7d7.png

Proa16_2017_Dec5a3.png.900d32c013672864a8b12bc19695f347.png

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On 12/4/2017 at 2:17 PM, Panoramix said:

Some people do the bottom in strip planking and the rest in plywood. Not sure how they do the junction though. 

Bieker, for example.  Russell would know the strip/ply layup...

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8 hours ago, ProaSailor said:

I'd rather see methods that give predictable results without relying on the skills of a surfboard shaper.

I can generate CAD (CNC) for panels like these, shown at 3/16" thickness.  Allowance for material thickness on hull length and beam is minor.

I wonder if the bottom and deck could be pre-assembled (taped and finished) with vertical sleeves (tabs, bulkheads) that fit inside the topside plywood pieces?  And where you want to terminate those bottom surface strips, to finish and fair it with filler?

Proa16_2017_Dec5a.png.8a892f8f292a8d4b0fe471683ff50136.pngProa16_2017_Dec5a2.png.f1881e8593116cd398bb36199e80c7d7.png

Proa16_2017_Dec5a3.png.900d32c013672864a8b12bc19695f347.png

Unless you are going series production, why? As an owner who commissioned a great boat, I can tell you nobody cares except you.  Sad but true...

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12 hours ago, Amati said:

Unless you are going series production, why? As an owner who commissioned a great boat, I can tell you nobody cares except you.  Sad but true...

I always think in terms of series production.  So much more efficient to build more than one, considering all the expertise involved in both design and fabrication.  Some sailors enjoy sailing more than building.

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The 0.00002342423 type Gaussian curvature is very developable.

For the monohull I showed I was working to the min bend radius of 1/4" plywood (about 24") as my goal to get the rounded stern.

Setting the Gaussian curvature to a range of 0 to -0.1 is odd to me. I think this would give you a false sense of how flat the stern in. Because I never do this, I made a simple surface. At one end it's totally flat and the other end it gets all curved and twisty.

Here are screenshots using "Auto" Gaussian curvature and then forcing it to several different values. I think the Auto gives me the best picture of where the curvature is compared to the whole surface. For those not following along at home the green shade is very flat and red and blue shades are different curvatures at opposite ends of the spectrum (convex and concave)

"Auto" range:

rhino1.jpg

 

Range from 0.1 to 0:

rhino2.jpg

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Zonk,

    I'm delving into the mysteries of the Rhino Gaussian stuff myself and find AUTO to give me a clearer idea of what is going on. I deliberately tortured a bit to the bottom of the stem on this design to keep the profile from being dead flat. 

image.thumb.png.cae4edbc7d87775cdad877134fd5f644.png

First image is when I assign the hull to the curvature tool and note the range, pretty small so I don't think it would be hard to do with stitch and glue ply. But then look at the color coding when I click on the auto range button which remaps the coloring and shows more subtle compounding at the ends of the middle strake. However you can see that the numerical values for the curvature range have decreased greatly.

     Orca gives me the real time display you see in the upper left hand corner of Section Area Curve and displacement as well as a host of other data. I should change to wetted surf and Cp for this rowing hull.

image.thumb.png.e6d39393e9f8700e8cc83e8a878e43a9.png

image.thumb.png.b15b0dac0b62716f7828cafd858a51f2.png

I'm about ready to take this project into Rhino6 WIP but aren't sure if I will lose my Orca3d functionality there. 

 

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No, but I might build a prototype just to be sure it all works as planned. Coming from you that is high praise Russ!  Sometimes I look at it and think it needs more sheer but then in 3d is looks just fine. It needs a pretty good payload capacity and I want it to row well but it should be able to take up to 4-6 HP as a tender. There is interest in using one of the small Torqeedo electrics as well. I built a Bolger Nymph dink ages ago and used it when I lived aboard. Pretty chunky little thing but rowed surprisingly well yet still carried myself, wife and young child when needed. This  pram shows a lot of influence of the 7'9" Nymph just stretched out to around 11'. This pram started with a full bow but I chopped the bow off to get the prow bow you see. Your PT 11 is a real beauty that I have long admired but this is intended as more of a workhorse hence the fuller shapes. 

Bolger Nymph

Image result for bolger nymph plans

   I guess my pram is just a stretched Nymph with an extra panel per side. Maybe a Nymph crossed with a Nutshell in some respects. You will appreciate this bright finished  german built Nutshell!

Image result for nutshell pram

    I hadn't thought of the Nutshell when I modeled my pram and it is interesting to compare the strake widths to the Nutshell. I have to admit that I was thinking more of the SCAMP without the heavily tumblehome that the top sheerstrake adds. Less rocker than any of them in hopes of planing with 6HP. I'll keep you posted, as it is still very much a WIP.

 

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On 12/6/2017 at 4:04 AM, Amati said:

Bieker, for example.  Russell would know the strip/ply layup...

Russell, if you are ready to share, I would be curious to know...

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9 hours ago, Rasputin22 said:

Image result for bolger nymph plans

  Image result for nutshell pram

    I hadn't thought of the Nutshell when I modeled my pram and it is interesting to compare the strake widths to the Nutshell. I have to admit that I was thinking more of the SCAMP without the heavily tumblehome that the top sheerstrake adds. Less rocker than any of them in hopes of planing with 6HP. I'll keep you posted, as it is still very much a WIP.

 

I'm not so much interested in planing per se, but it's readily apparent to me that less rocker is helpful when using an outboard of any size  (which, of course, was NOT the usual intent of most of these pram designs).  So I'll be interested in hearing how it works out in real life.

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3 hours ago, Panoramix said:

Russell, if you are ready to share, I would be curious to know...

The lightest and easiest way would be 4 mm plywood as Proa has drawn. The wide topside panel would probably need a stringer. It's pretty amazing how light a plywood hull can be.

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Russell, when I built boats for money, I got tired of being ripped of by part timers who would splash a female mold off one of my hulls and pop out cheesy copies so I went back to the miracle fiber W, and built plywood dory type hulls.  !6' 40lbs . all up.  They splashed, 125lb. copies that oilcanned  like noodles and couldn't give them away.  There is something wonderful about a material that takes a hundred years of flexing to make, and is stiff and warm to the touch.  Wood is good.  Aloha, Guerdon.

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So true guerdon! That pram I showed may end up getting produced in fg but at least I know in advance. Hard to beat good ply/epoxy for ease of building (relatively) and stiffness for the weight. Too bad good marine ply has gotten so expensive. Long live Miracle Fiber W! 

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Rasputin, If you contact Joubert plywood, you may find that you can still do it reasonably  especially if you used the new generation of epoxies.  Good luck to you.

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1/2 angle of entry, ama rocker and articulation?

Looking at cross-sections on these proa hulls the other day, esp. the first one from the bow, got me thinking that maybe it was too fat too fast?  So I added a 1/2 angle of entry widget to the GH model and found that it was 15.5 degrees.  I tried slimming it by moving a parameter point aft and dropped the 1/2 angle of entry to 12 degrees with little loss of displacement.  Did the same thing on the ama and then noticed on a top view that with the bow knuckle above the waterline, the 1/2 angle of entry isn't relevant.  The water is encountering the bottom surfaces first, not the topsides where I measured 1/2 angle of entry...

Maybe 1/2 angle of entry isn't as relevant on a proa ama as other factors, but to the extent that it is, reducing rocker brings the bow knuckle down so the stem is cutting the water more deeply.  This is a return to earlier shapes posted more than a week ago.

Proa16_2017_Dec7d1.thumb.png.dcf10db3758a0f93b9919e94aa409805.png

Proa16_2017_Dec7d2.thumb.png.5bd0764be749b38fdc2ec8ef739637f6.png

Proa16_2017_Dec7c1.png.5fb85b187a650292bd4400eeffdc25ef.pngProa16_2017_Dec7c2.png.9a465597ce38731948e14ac502f3c93e.png

Which brings up the last part of these musings - ama articulation.  Maybe the articulating amas seen in traditional canoes make keel rocker in the ama less necessary than would be expected on modern boats with stiff crossbeams?  They usually have three cross members connected to form a twisting platform that allows the ama to respond rapidly to changes in water surface angle.  Would love to see a modern version of that?

Proa16_2017_Dec8a.thumb.png.edd110e637a29b7cb248e769397d0594.png

From this video posted earlier: https://www.youtube.com/watch?v=nb0IhuqdTFQ

video_525.thumb.jpg.97cb4b30747fbe19d4b370dd6685fab2.jpg

video_527.thumb.jpg.e3e70f6f3c20aaf1b4e1934d2d88e809.jpg

video_548.thumb.jpg.68a3dc279cbeef9b5a728cb6cbe0398c.jpg

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I think you are on the right track.  I did a pivoting outrigger with drag links but it sold before I could test it.  The flex reality is one of the better aspects of Proas.

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57 minutes ago, ProaSailor said:

Which brings up the last part of these musings - ama articulation.  Maybe the articulating amas seen in traditional canoes make keel rocker in the ama less necessary than would be expected on modern boats with stiff crossbeams?  They usually have three cross members connected to form a twisting platform that allows the ama to respond rapidly to changes in water surface angle.  Would love to see a modern version of that?

Proa16_2017_Dec8a.thumb.png.edd110e637a29b7cb248e769397d0594.png

Another way to consider an articulated proa ama is a 4' X 8' panel/platform, rigidly attached at both ends (hulls), ~two inches thick (arbitrary), with well behaved (damped) twist characteristics, courtesy of composite engineering... and perhaps some lashed lines here and there?

Proa16_2017_Dec8b.thumb.png.d907993c1e699ff4fafa1426412d72b1.png

Proa16_2017_Dec8b2.thumb.png.2904d7fd2bf1ac1a7314bd695cb1a90e.png

Proa16_2017_Dec8b3.thumb.jpg.4479f2d0cc3eea606d9b8b44d8b8b8e7.jpg

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Another still from that same video showing details of a system commonly used on the Marshall Islands proas, with two "upper" beams interspersed and suspended between the bottom three, all lashed elaborately.  Looks like a possibility for a parallelogram at the end, where lashings could be a damping factor (or favor bow-up attitude on appropriate tack?).  Fascinating to see how responsive and effective they are at speed.

video_702.thumb.jpg.4bfb6e623a62742bbe463db50969fbbb.jpg

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2 hours ago, ProaSailor said:

Another way to consider an articulated proa ama is a 4' X 8' panel/platform, rigidly attached at both ends (hulls), ~two inches thick (arbitrary), with well behaved (damped) twist characteristics, courtesy of composite engineering... and perhaps some lashed lines here and there?

Is there any point to a structure like this?  Five beams rigidly attached to the main hull, the intent being that bend and twist gets easier outboard where two beams connect to the ama.  Slightly over-sized composite 2X4s as shown, epoxied together if possible, lashed if necessary for ama articulation movement.

Proa16_2017_Dec8c.thumb.jpg.3fca7f580ef9825dbae0163bc966043e.jpg

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1 hour ago, ProaSailor said:

Is there any point to a structure like this?  Five beams rigidly attached to the main hull, the intent being that bend and twist gets easier outboard where two beams connect to the ama.  Slightly over-sized composite 2X4s as shown, epoxied together if possible, lashed if necessary for ama articulation movement.

Proa16_2017_Dec8c.thumb.jpg.3fca7f580ef9825dbae0163bc966043e.jpg

Proa16_2017_Dec8c2.thumb.jpg.b57fa6fa981cfa51dc741d903f5b2ef5.jpg

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2 hours ago, Panoramix said:

Proa, I like your design.

Thanks.  Hard to know how a framework like that will behave until you build it (or build a physical model), attending to important details like tightness of connections.  Looks a bit sketchy to me for several reasons, heavy and not as strong as it could be.

This is a better way (below).  More conventional modern construction, two beams/planks rigidly connected to main hull, tapered to be stiff fore and aft and oriented to be flexible up and down.  Having the crossbeam tips close together magnifies ama pitch rotation from minimal beam deflection, effectively articulating the ama.  The beam tips are intended to flex up and down a few inches (to be calculated based on ama bow height maximum) so composite layers can be thicker near the main hull, thinner near the ama as needed.

The struts in the ama are parts of a tetrahedron, very strong connecting structures with an important detail: it has two inline connection points to each crossbeam.  These can act like an axle if the connection is flexible, allowing just a slight bit of movement to accommodate the ama's changes in pitch.

Proa16_2017_Dec9a.thumb.jpg.19b9eede0b54cefacfd78d94547fc455.jpgProa16_2017_Dec9a2.thumb.jpg.02e2ec7c388392aa311c4b1363bac54c.jpgProa16_2017_Dec9a3.thumb.jpg.ec99b3965ca00117350971a85b97d503.jpg

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I'm not sure about the details between crossbeam and tetrahedron struts...   Good place for a lashing (or straps as shown on Hawaiian canoe) along a pivot line between the two, if a good linear bearing surface is provided.  They are shown as pipes but don't need to be.  Drawing them precisely is old hat, GH code written a couple of years ago that adapts quickly.

Beams like this that allow the ama to pitch independently of the main hull aren't difficult.  As more structure is added, however, on the main hull between the crossbeams, it gets easier if those beams are as rigid as possible.  The ama "articulation" effect is lost.  That independent pitching makes amas work without high bows and with minimal rocker.

Proa16_2017_Dec9b.thumb.jpg.aac840d7cec3494ca47ca721238a4fcb.jpgProa16_2017_Dec9b2.thumb.jpg.36678607c7ef45e426d79f5fc2b25507.jpg

003.thumb.JPG.04868f68373ea796c1944c2bf7c4dd7a.JPG

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You might consider tubular glass arches made from pool fun noodle mandrels covered with biaxial strips oriented along the stress axis.  It was quick, stout, light and cheap.  The secret is to wet out the biaxial on wax paper, and wrap it around the noodles which are tacked in place prior with epoxy fillets.  Go for it.

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5 hours ago, ProaSailor said:

The struts in the ama are parts of a tetrahedron, very strong connecting structures with an important detail: it has two inline connection points to each crossbeam.  These can act like an axle if the connection is flexible, allowing just a slight bit of movement to accommodate the ama's changes in pitch.

This version uses the tetrahedron lines to create a pair of triangular surfaces instead of struts, meeting as before at the keel.  There is a tie-down beam between the two at the top for strapping on the crossbeam, but it's an obvious obstacle for waves so better to skip that and tie directly from crossbeam to triangle supports somehow?  All the sharp corners need a router to take the edges off.

Proa16_2017_Dec9c3.png.73c307f825c8c018b6da9c8f517ce8a8.pngProa16_2017_Dec9c.thumb.jpg.440ae03a1458477fb82597691b422a84.jpg

Proa16_2017_Dec9c2.thumb.jpg.2d4421250399c30d4dec6a083864de46.jpg

 

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6 hours ago, ProaSailor said:

Thanks.  Hard to know how a framework like that will behave until you build it (or build a physical model), attending to important details like tightness of connections.  Looks a bit sketchy to me for several reasons, heavy and not as strong as it could be.

This is a better way (below).  More conventional modern construction, two beams/planks rigidly connected to main hull, tapered to be stiff fore and aft and oriented to be flexible up and down.  Having the crossbeam tips close together magnifies ama pitch rotation from minimal beam deflection, effectively articulating the ama.  The beam tips are intended to flex up and down a few inches (to be calculated based on ama bow height maximum) so composite layers can be thicker near the main hull, thinner near the ama as needed.

The struts in the ama are parts of a tetrahedron, very strong connecting structures with an important detail: it has two inline connection points to each crossbeam.  These can act like an axle if the connection is flexible, allowing just a slight bit of movement to accommodate the ama's changes in pitch.

Proa16_2017_Dec9a.thumb.jpg.19b9eede0b54cefacfd78d94547fc455.jpgProa16_2017_Dec9a2.thumb.jpg.02e2ec7c388392aa311c4b1363bac54c.jpgProa16_2017_Dec9a3.thumb.jpg.ec99b3965ca00117350971a85b97d503.jpg

I was commenting mainly on the hulls.

For the ama pitch rotation, I am not sure that you actually need tetrahedrons, a rectangular timber beam has a relatively low torsional stiffness and it may well be low enough to allow enough rotation of the ama

.

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1 hour ago, Panoramix said:

For the ama pitch rotation, I am not sure that you actually need tetrahedrons, a rectangular timber beam has a relatively low torsional stiffness and it may well be low enough to allow enough rotation of the ama.

You may be right, but since the main hull is higher than the ama, you have to either bend the crossbeams down to it or reach up for them from the ama with some kind of connecting structure, sturdy with minimal windage and wave resistance.  Easier to over-build for stiffness than just the right amount of flex, twist and strength, but trial and error (and perhaps composite engineering) works wonders.

Proa16_2017_Dec9d3.thumb.jpg.7098351ec35bc7bbc28c7acc24ea3e4f.jpg

P.S.  If you have a single post solution as an ama connection, I'd love to see it? I'm sure it can be done, but is it guaranteed bluewater rugged?

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54 minutes ago, ProaSailor said:

is it guaranteed bluewater rugged?

If I ever manufacture a boat like this, it might be a liability to use a phrase like "guaranteed bluewater rugged" in this context?

Proa16_2017_Dec9d4.thumb.jpg.7b377de7c1b6bcd1c75ed65d0499480e.jpg

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Why not go with a Ketterman style single carbon ama that does all the above through twist?  Or you could go with an Adrenaline style rotating ama?

Anyway, I went with the plank so the ama would have give in waves.  Granted the shape isn’t very good, but I wanted to try it out as is before I take the belt sander to it, or glue a more typical ama shape to it.

I’ll probably wish  I’d used hemlock and not mahogany for the plank, but mahogany was what I had on hand...

The blessings of solid balsa....

i attached it with dowlings drilled and glued about 6” long like this:

|||

(profile view)

from the top

...

(longitudinally)

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7 minutes ago, Amati said:

Why not go with a Ketterman style single carbon ama that does all the above through twist?

Single crossbeam (not ama)?

7 minutes ago, Amati said:

i attached it with dowlings drilled and glued about 6” long like this:

|||

(profile view)

from the top

...

(longitudinally)

Great CAD imagery.

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One big crossbeam, but no torsion, a more complex system.

The web page seems to be down, maybe the project abandoned, but youtube remembers. There are several videos:

 

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1 hour ago, semelis said:

One big crossbeam, but no torsion, a more complex system.

The web page seems to be down, maybe the project abandoned, but youtube remembers. There are several videos:

 

Good find, interesting boat.  Not the most powerful rig.  I've consider that ama system too, pitching the ama under a stationary crossbeam (or two).  Would like to see those details.  I was thinking of a stationary hull center section, attached to rigid crossbeams, surrounded by a pitching full length hull (and other variations).   Seems like more relative motion, more danger of body parts being crushed?

Proa16_2017_Dec9d5.thumb.jpg.fbbe13587d9e407e241e8fc3e2867af7.jpg

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1 hour ago, ProaSailor said:

Single crossbeam (not ama)?

Great CAD imagery.

Sorry meant aka.  I’ll find some pics..

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Rasp,

You can also check "min radius" in the curvature analysis. I try to keep it above 24" for 1/4" plywood. But I will accept small areas of higher curvature like the red hot spot in your first image.

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11 hours ago, ProaSailor said:

Good find, interesting boat.  Not the most powerful rig.  I've consider that ama system too, pitching the ama under a stationary crossbeam (or two).  Would like to see those details.  I was thinking of a stationary hull center section, attached to rigid crossbeams, surrounded by a pitching full length hull (and other variations).   Seems like more relative motion, more danger of body parts being crushed?

 

The 12 m. proa was a scale model of a 60 m. cargo project, for the rig they recycled a crabclaw from another proa.

This model just had a hinge for the ama under the crossbeam tip, in another video is clearly seen, and I would say under-engineered. The full scale boat had a more complex arrangement with dumpers adjustable to the conditions.

I agree with the big relative motion being scary in some conditions, but the idea seems worth investigating.

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These two recent images show the hulls sitting heavy in the water... (453 + 269 = 722 lbs)

  • Main hull: LOA: 16', L/B Ratio: 16, BOA: 12", Draft: 9.7", Disp: 453 lbs, Cp: 0.63, Awp: 11.77 sq ft, WS: 26.8 sq ft, Srf Area: 62.5 sq ft, Volume: 16 cubic feet (1023 lbs), Srf/Vol Ratio: 3.9
  • Ama: LOA: 16', L/B Ratio: 18, BOA: 10.67", Draft: 8.33", Disp: 269 lbs, Cp: 0.62, Awp: 10.6 sq ft, WS: 20.9 sq ft, Srf Area: 40 sq ft, Volume: 7.25 cubic feet (463 lbs), Srf/Vol Ratio: 5.5

Proa16_2017_Dec9d3.jpgProa16_2017_Dec9d5.jpg

Compared to 1" less draft below, where the main hull bow knuckle is exactly at the waterline - still significant!  (390 + 212 = 602 lbs):

  • Main hull: LOA: 16', L/B Ratio: 16, BOA: 12", Draft: 8.7", Disp: 390 lbs, Cp: 0.61, Awp: 11.77 sq ft, WS: 24.1 sq ft, Srf Area: 62.5 sq ft, Volume: 16 cubic feet (1023 lbs), Srf/Vol Ratio: 3.9
  • Ama: LOA: 16', L/B Ratio: 18, BOA: 10.67", Draft: 7.33", Disp: 212 lbs, Cp: 0.62, Awp: 10.5 sq ft, WS: 18.2 sq ft, Srf Area: 40 sq ft, Volume: 7.25 cubic feet (463 lbs), Srf/Vol Ratio: 5.5

Proa16_2017_Dec10a3.thumb.jpg.2fa3ed0eaea7c8df456d4922758cc3e2.jpg

The hulls have considerable reserve buoyancy (volume!): 1023 + 463 = 1486 lbs.  Might make a nice car top river/lake fishing platform with motor alone?

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