Standup Zone Forum
General => The Shape Shack => Topic started by: PaddleSpot on March 30, 2018, 11:59:00 AM
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a trimaran SUP
Dreamt of it...
Had a few beers, drew a few sketches with my old buddy Pierrot...
Designed it on Shape3D...
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19' x 13"
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I like the concept, but 2 ama's might create more drag than you would be losing with the rounded hull?
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Hopefully and with a little practice, only one ama will touch the water
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Step 2 : preshape by Atua.Cores near Bordeaux
https://www.facebook.com/atuacores/videos/10154891560062172/
https://www.facebook.com/atuacores/videos/10155040664627172/
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Step 3 :push the furniture
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Step 4...
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Step 5 ...
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Almost there...
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Et voilà :-)
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https://www.facebook.com/PaddleSpot/videos/829746850569169/
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More on https://www.facebook.com/PaddleSpot :)
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Wow, less than 2 hours from drawing board to totally bored... ;D
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Yeap ! I need a new idea, ASAP !
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Perhaps a trimaran-foil? We'll check back in an hour.
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What is the volume of the main hull?
I thought about doing something similar only much narrower main hull and amas much shorter and closer to the main hull.
Standing on the amas rather than on the main hull.
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Perhaps a trimaran-foil? We'll check back in an hour.
;D
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What is the volume of the main hull?
The underwater volume is 115 liters
I thought about doing something similar only much narrower main hull and amas much shorter and closer to the main hull.
Standing on the amas rather than on the main hull.
I don't know. The next step would be to reduce the main hull and get... a standamaran
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Did you like it? Was it fast? I didn't see a fin? I watched your vids on Facebook - I was curious what a fall would be like - you did that, I see you can clear the ama :D It also looks like you could try one ama, like an OC Canoe?
A lot of work to "try it out" - I'm impressed.
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I think I'm falling in love with it :-)
I'll try to row 30 or 40 km monday to get an idea of the average speed on a long distance, but it's fast. I still have to make a few adjustments on the platform, it's too wide (23") but a bit short.
I'm trying different fin configurations, based on this set. I still have to figure out how to control the rudder.
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Only 1 fin this time, just under the back iato
It could be used with one ama, but I'm afraid it's dangerous for both the guy and the ama when capsizing
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Does it "steer" by touching one ama or the other?
Took me a bit to visualize "dangerous" in a capsize - but then I realized, the one ama could go vertical and you would have to high-jump it or duck under it - or eek! maybe get smacked by it if you fell with the direction of the roll.
Some the pics show both ama touching, some one - can both fly out of the water? or is 13" just too tippy for that?
Facebook isn't translating to English for me but I can get a good idea what is going on. Watched your video where you collected an armload of canoe paddles - that cracked me up.
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Bean was probably joking but you'd have a lot less drag with a foil ama--a little float for initial stabilization and then a surface-piercing foil for stabilization. You could do that with just one set of iakos. Probably best to do it with a single front iako so it wouldn't hit you if it hulis. When and if I get my OC1 to Hood River I want to experiment with that. Current design has a lot of drag from the interference waves between the ama and the hull--they're close enough so the bow waves can't pass behind, and the amas are very long so the wave probably even drags in rebound.
The main reason sailing cats are so wide (besides resisting tip from the sail) is interference drag. The SIC Standamaran suffers from it.
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Does it "steer" by touching one ama or the other?
So far, it didn't feel so, but I have so much to learn.
Took me a bit to visualize "dangerous" in a capsize - but then I realized, the one ama could go vertical and you would have to high-jump it or duck under it - or eek! maybe get smacked by it if you fell with the direction of the roll.
I'm too old for high jumps or quick ducking :-)
Some the pics show both ama touching, some one - can both fly out of the water? or is 13" just too tippy for that?
Probably to tippy for me, but I'll ask Olivia Piana to try next time I meet her on the water. If anyone can do it, she's that one. But definitely not an option for me.
Facebook isn't translating to English for me but I can get a good idea what is going on. Watched your video where you collected an armload of canoe paddles - that cracked me up.
On the Ardèche river. Not my best race ever,but I made a lot of friends;-)
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Bean was probably joking but you'd have a lot less drag with a foil ama--a little float for initial stabilization and then a surface-piercing foil for stabilization. You could do that with just one set of iakos. Probably best to do it with a single front iako so it wouldn't hit you if it hulis.
Probably so. From the start,I had in mind to be able to easily change everything. Different amas, longer iatos, etc....
Current design has a lot of drag from the interference waves between the ama and the hull--they're close enough so the bow waves can't pass behind, and the amas are very long so the wave probably even drags in rebound.
I can try with a much longer iato, but I'm not sure that with a lenght/width ratio of 20 and at relatively low speed the bow wave is significant. The standamaran is 28" wide, hence only 14" between the bows. I currently have 3' between hull and ama bows. I can push it up to 5' on one side for the tests.
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Actually I had this wave interference issue in mind when I designed the "board", specially since you already mentioned it somewhere on this forum, PonoBill.
That's why I discarded the catamaran option from the start.
Then I picked standard carbone tubes, hence the 2 meter width, but I can try an asymetrical setting with a few more dyneema ropes. What distance would you suggest ?
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Facebook isn't translating to English for me but I can get a good idea what is going on.
what is going on can be summarized in two words : "Dordogne Intégrale"
An incredible 130 km (80 miles? ) race in 1 day down the river Dordogne.
Two years in a row, these beautiful landscapes were spoiled by the permanent vision of the tail of the board of my friend the world class shaper Patrice Remoiville, and his boardshort.
2 years ago I had a 14', he used an old 17'. I arrived a few seconds behind him after a 12h40 race.
Last year I built a 18', he designed a splendid 17', I finished 5' behind him after another 12h40 race (faster boards but less current)
Enough is enough :)
Either the trimaran will explode in the white waters of the first part of the race, or I will kick Patrice's short out of my horizon ! A beer is in stake !
https://www.facebook.com/pg/Dordogne-Intégrale-1559022421079012
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Bean was probably joking but you'd have a lot less drag with a foil ama--a little float for initial stabilization and then a surface-piercing foil for stabilization. You could do that with just one set of iakos. Probably best to do it with a single front iako so it wouldn't hit you if it hulis.
Probably so. From the start,I had in mind to be able to easily change everything. Different amas, longer iatos, etc....
Current design has a lot of drag from the interference waves between the ama and the hull--they're close enough so the bow waves can't pass behind, and the amas are very long so the wave probably even drags in rebound.
I can try with a much longer iato, but I'm not sure that with a lenght/width ratio of 20 and at relatively low speed the bow wave is significant. The standamaran is 28" wide, hence only 14" between the bows. I currently have 3' between hull and ama bows. I can push it up to 5' on one side for the tests.
Standamaran has 18" between bows but who's counting, still, as Bill says, produce interference drag. That said, I'd take a Standamaran over this design every time unless it's strictly flatwater.
Too many chances for injuries otherwise.
I would rather explore the attached design where you stand on the ama (and fly the other one), seem much more usable and less injury prone. Not sure how much hit you'll take on speed with
that design, but judging by how fast the Standamaran is compare to my other 16 in many conditions, this design could probably be more efficient and comfortable.
But kudos to you for pushing the envelope, I love seeing this stuff and I'm sure you're having ton of fun with it. 8)
Bean was probably joking but you'd have a lot less drag with a foil ama--a little float for initial stabilization and then a surface-piercing foil for stabilization. You could do that with just one set of iakos. Probably best to do it with a single front iako so it wouldn't hit you if it hulis.
Trying to imagine how that looks like?
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I would rather explore the attached design where you stand on the ama (and fly the other one), seem much more usable and less injury prone.
How can you stand on a ama if its not at least 100 liters :) ? My amas are 12' long and only 45 liters.
I don't see so many chances for injuries. The board is so stable you can ride it on one foot, and it's only plastic. I could add patches of deck pad on the iatos just in case.
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I would rather explore the attached design where you stand on the ama (and fly the other one), seem much more usable and less injury prone.
How can you stand on a ama if its not at least 100 liters :) ? My amas are 12' long and only 45 liters.
I don't see so many chances for injuries. The board is so stable you can ride it on one foot, and it's only plastic. I could add patches of deck pad on the iatos just in case.
If you look on the design above, you're not really standing on the ama, weight is distributed. 45 liters sounds doable.
Going back to your board, I'm sure it is super stable and you can ride it in flat water with your eyes closed no problem, but what happens when
the water gets rough, like open ocean rough? I see the chances of falling and falling the wrong way increase substantially.
If it's not where you're aiming with this design and it only meant for flat water, then I could see myself on this board having fun :)
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You're probably right about the minimal bow wave with that length/width ratio. I've never found any quantitative information on narrow hulls and why they don't generate a bow wave they need to climb over, it just gets mentioned as a fact, so this feels like guesswork, but most cats and trimarans have ratios of 10-1 or greater and they still have interference drag. I read a couple of papers on interference when Mark Raaphorst built the standamaran, you could google for them, but they're a bit dense. The upshot was there isn't much you can do for a catamaran but a trimaran can have offset hulls.
There may not be a huge improvement in performance by reducing drag, but since you have a beer riding on this thing it might be worth some added effort.
The typical way to minimize interference drag other than wide hull spacing is to offset the hulls in an arrowhead pattern or some other configuration that causes most of the generated wave energy to miss the ama hulls. Your amas are very long, so that might be hard to do. I'd say try something half that length or shorter. But you could test the concept with your current amas by moving the front iako to just behind your feet and the second iako to the tail of the main hull. You could just do time trials, or if you feel all science-y drag it beside a boat with a fish scale on a windsurfing mast.
Either way it looks like great fun. Best of luck with it and keep us posted.
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You're probably right about the minimal bow wave with that length/width ratio.
I did a few visual tests today with a friend on absolutely flat water, at a steady cruising speed of 8.5 km/h, the bow waves are really small with a very acute angle, and actually meet behind the iato !
Which doesn't mean there are no other hidden interferences. I can't reduce the lenght of the amas since I need this space between the iatos to paddle comfortably. But I can try a longer iato.
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If you put the front Iako behind your feet you'll have lots of space to paddle, you'd have an automatic Dave Kalama stroke length limiter and the bow wave will largely miss the Ama. The most visible wave is not the only energy being transferred to the water and the angle of the most visible wave isn't the only energy path. I won't mix quantum physics with the real world, but the energy fans out from the bow--not a sum of all histories, but not a straight line either. I can't really tell from the photos since your paddle strokes are on the side with visible water, but it looks like there's an interference pattern similar to what I saw with the Standamaran.
Again, this may make no practical difference in speed, but you've gone this far with your effort, a little additional quixotic effort might yield some performance benefit.
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PonoBill, that's what an automatic Dave Kalama stroke length limiter would bring me :-)
https://www.facebook.com/PaddleSpot/videos/828637374013450/
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The platform has been quickly modified...
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I also imagined different design, so go 4 it... https://www.facebook.com/Hi.fun.hydroworks/photos/pcb.1107013132806301/1107012959472985/?type=3&theater
Tested on a 80mile river race, needs some improvement on stabilizers placement with some option with foils or single amas, let's see and try...so far it works unreal on flat water, so stable... weighs about 16 kgs /35 lbs total ,16'9'' long (5,03 m) without rudder... and 2,1 m (almost 7' wide) connected with bamboo.
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Very cool. You are probably getting a good amount of drag from the bamboo touching the water. You can see in your photos that there is a good splash left by the bamboo.
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Very cool. You are probably getting a good amount of drag from the bamboo touching the water. You can see in your photos that there is a good splash left by the bamboo.
absolutely right, I need to modify that problem, thinking about raising stabilizers by about 1 inch 1/2 and adding foils below...
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That guy was a pioneer in that matter with a modified old surfski...http://www.forumdesup.com/t163p25-proto-sup-multicoque?highlight=multicoque last development with hydrofoils.
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That guy was a pioneer in that matter with a modified old surfski...http://www.forumdesup.com/t163p25-proto-sup-multicoque?highlight=multicoque last development with hydrofoils.
The foils have to cant inward, not outward so that as the hull rolls, lift increases on the side that one wants raised, a la Hydroptre. Or curve upwards like a leeward side DSS foil in some sailboats.
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That guy was a pioneer in that matter with a modified old surfski...http://www.forumdesup.com/t163p25-proto-sup-multicoque?highlight=multicoque last development with hydrofoils.
The foils have to cant inward, not outward so that as the hull rolls, lift increases on the side that one wants raised, a la Hydroptre. Or curve upwards like a leeward side DSS foil in some sailboats.
agree but... when hull rolls on one side foil moves downwards together with roll direction, so incidence and lift increase so roll tends to be stopped... my intention is to use both ways: one transverse and on each side v-shaped foils... let's try!
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So far I added 2 small 12" T-foils 2 inches below after amas ( raised them by 1 inch)... on flat conditions those almost dont touch water and fore amas don't touch too... Still needs to improve: 2 options: 1- replace after amas by V foils ( as explained previous post)- 2 replace those 4 amas by 2 longer, will work better in open ocean conditions!
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> Tested on a 80mile river race, needs some improvement on stabilizers placement
Pierre is too modest, he ranked 23rd out of 170 SUPs on the 80 miles "Dordogne intégrale" last week, with a broken rudder, heavy rain and front wind (our trimarans are definitely not at their best upwind ).
And he forgot to mention that he built this thing in 10 days and it was his first navigation :-)
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Pierre, it's too bad we didn't have time to compare our creatures :) I specially enjoyed the white water par of the race, the tri' is sooooooo stable.
Can't wait for my first DW !
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Variation on a theme...
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Big smile PS, so you must be doing it right!
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It was just a first test with amas made of PVC pipes, but it was definitely fun. I just received carbon tubes, and am starting working on a seat and foot rests, and maybe a rudder.
It should be possible to turn the trimaran SUP into an OC1 in less than 5 minutes :-)
Now I'm looking for a Va'a iato to make a downwinder version.
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And today, it was a "stand up Va'a"
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Seems like you'd be stuck paddling mostly on the one side?
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First tests of the 2019-flatwater version, based on a marathon kayak ;D
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I love it. Keep creating. That board / Osup-1 looks really refined. The ama's and boardlook like a production model.
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Glagla race 2019
credit @paddleleague/@kalamurza_ph
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Nutty as a fruitcake. I love it. Did anything definitive come out of your X-foil experiments? I might have to do some silly stuff this summer. I have a radically butchered Speedboard I can cut up to make silly stuff from.
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Hi PonoBill
Sorry, no foil experiments yet. This trimaran is designed for the Dordogne Integrale race 2019 special 10th anniversary edition (350 km / 217 miles instead of the usual 130 km) , where I shall need stability (= confort, no energy loss in keeping my balance) with a minimum drag. Think of it as a fuel-efficient long distance SUP.
it is probably also very fast, but would need a better paddler than me.
The idea is to inject some kayak DNA into SUP design ( these guys have been designing hulls for centuries, they probably know one or two things...) and see what happens. Look at this video, at 2:30. I had the luck to buy this black beauty.
https://www.facebook.com/canoemarathonportugal/videos/2228752067371605?t=145
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"Dordogne Intégrale", 350 km race in 3 days, done :-)
https://www.facebook.com/dordogneintegrale/videos/632841263846136/ (https://www.facebook.com/dordogneintegrale/videos/632841263846136/)
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Well done Olivier ........ That was one long ass paddle. My body would be trashed for weeks after that. But for some stupid reason I would want to do it too ;D
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Actually with the trimaran it was really easy, I was able to follow my regular SUP buddies, needing one paddle stroke when they needed two :)
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Actually with the trimaran it was really easy, I was able to follow my regular SUP buddies, needing one paddle stroke when they needed two :)
Wow, one paddle stroke to their two is amazing! Have you thought about configuring it with a windsurf rig? You already have the rudder and you could replace the surfboard fin with something larger for clawing upwind.