Author Topic: Trimaran SUP  (Read 28847 times)

burchas

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Re: Trimaran SUP
« Reply #15 on: March 30, 2018, 05:37:51 PM »
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.
in progress...

PaddleSpot

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Re: Trimaran SUP
« Reply #16 on: March 30, 2018, 09:36:31 PM »
Perhaps a trimaran-foil?  We'll check back in an hour.

 ;D
Olivier Drut
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Re: Trimaran SUP
« Reply #17 on: March 30, 2018, 10:02:04 PM »
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
Olivier Drut
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deepmud

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Re: Trimaran SUP
« Reply #18 on: March 31, 2018, 12:16:14 PM »
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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Re: Trimaran SUP
« Reply #19 on: March 31, 2018, 01:16:45 PM »
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.


Olivier Drut
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Re: Trimaran SUP
« Reply #20 on: March 31, 2018, 01:30:17 PM »
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
Olivier Drut
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deepmud

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Re: Trimaran SUP
« Reply #21 on: March 31, 2018, 02:22:43 PM »
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.

PonoBill

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Re: Trimaran SUP
« Reply #22 on: March 31, 2018, 04:24:42 PM »
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.
« Last Edit: March 31, 2018, 04:29:22 PM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PaddleSpot

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Re: Trimaran SUP
« Reply #23 on: April 01, 2018, 06:33:15 AM »
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;-)
Olivier Drut
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Re: Trimaran SUP
« Reply #24 on: April 01, 2018, 07:12:57 AM »
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.

Olivier Drut
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Re: Trimaran SUP
« Reply #25 on: April 01, 2018, 07:44:21 AM »
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 ?
Olivier Drut
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Re: Trimaran SUP
« Reply #26 on: April 01, 2018, 08:30:14 AM »
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
Olivier Drut
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burchas

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Re: Trimaran SUP
« Reply #27 on: April 01, 2018, 10:07:57 AM »
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?
« Last Edit: April 01, 2018, 10:10:08 AM by burchas »
in progress...

PaddleSpot

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Re: Trimaran SUP
« Reply #28 on: April 01, 2018, 11:48:53 AM »

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.

Olivier Drut
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burchas

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Re: Trimaran SUP
« Reply #29 on: April 01, 2018, 01:05:00 PM »

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 :)
in progress...

 


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