Trimaran Design

[rapscallion]

I am interested in building a trimaran. I know about the F22, F24, and the dragonfly designs, but i was wondering if there were any other interesting designs out there. I would be interested in designs from 16' to 27' LOA.

I figured I should start with a smaller 2 person tri and attempt the larger boat after i have some experience with boatbuilding.

Check these out:
Kurt Hughes Daysailer Tri's
Address:http://www.multihulldesigns.com/stock/daysailer.html Changed:4:48 PM on Sunday, November 26, 2006

[fhrussell]

Try this...fast boat, simple build, and relatively inexpensive.'

http://multimarine.com/L-7/L7.html

[henrikb]

How about this one..?
Building first boat at the moment...

[Raggi_Thor]

Henrik, that's an interesting looking tri.
Are the amas the same length as the main hull?
Isn't that quite unusual?

[henrikb]

I think that there are only advantages with long amas, better longitudal stability for example.
When looking at other designs, like the SeaCart 30 and the bigger 60-footers, the amas are equal in length to the main hull.
I am designing the tri together with a friend, the main hull is already built and tha amas are next! We had some second thoughts on the ama volume, from the beginning it was 250% of total displacement, but we are working on a 200% version at the moment, which seems to be fine, and looks better also!

[jamez]

Hi Rapscallion
Some other designs you might want to check out:

Tritium 720 http://www.paolobisol.com/tritium720_en.htm

Eric Lerouge Pulsar 26, and 23.

Ray Kendrick has several designs in your size range http://www.kendrickdesign.com.au/

Ed Horstman also has a few - some of which are trailable.

Dick Newick has a couple of less conventional designs B2 and Spark and of course there is always the Tremolino

[jamez]

Further to that last post if you are happy with something a little more basic built of ply:
Bernard Rhodes Kliss 3, TF Jones night heron and Hummingbird, Bill Kristofferson Kismet T24, John Marples Seaclipper 28. Marples has another design the CC26 which uses pre molded hull panels which can be built from veneer or ply.

HenrickB your boat looks pretty cool. Are you going to offer plans at all?

[rapscallion]

Originally Posted by henrikb

How about this one..?
Building first boat at the moment...

That is a good looking boat!

I want to build a composite boat as well; How long did it take you to build the molds?

The L7 has some nice features. I like the 3 furling sails, and the method used to retract the amas. I wish there was a more room in the cabin however. I was looking for s sporty "cruiser." So I was hoping to add some volume to a design similar to that. I was hoping for a bunk under the cockpit and about 5'11" headroom.

I also like the idea of high volume amas; the designer seems to believe it makes the L7 a faster boat, do you guys buy that?

I'm a Chemist, I know a little about polymers, but I don't know much about boatbuilding. Can you guys recommend any books on building composite boats?

This may be a really stupid question..... I was just wondering if there was a way to cut down on how much time it took to build a mold by simply stringing up fabric in a simple framework and spraying epoxy onto the fabric making it solid. I worked at an old school sail loft and that was how they would figure out how to cut the broadseams on sails. They would lay the Dacron over Bows that represented the sailshape, and cut the fabric to cover the bows.

I'm just trying to figure out how this works I guess.... Thanks for the input thus far.

[Chris Ostlind]

Rapscallion,

Perhaps there is something in this collection of designs I have done in this area that might interest you?

The Fast 17 is a very quick solo or two-up boat for day sailing. It uses a rig from a an 18' beach cat of your choosing

The A18 is a two-up design meant for coastal cruising utilizing a rig from a Hobie 16.

The A21 is a two person, lightweight, folding trimaran with twin, self-supporting masts and cruising level sail area.

The Cardiff 21 utilizes a rig from an 18-20' beach cat and is a demountable design with a rapid assembly function.

The Z65 is a full-cabin, 21'4" folding tri which makes use of the hulls, rig and hardware from a 20' beach cat such a Tornado, Nacra or Hobie. This boat can be built and operational for thousands of dollars less than the L7 and especially, the long awaited F22 design from Ian Farrier. You buy a used, 20' beach cat in top condition, build the main hull and you are off sailing, long before the two boats mentioned.

There is also a planned 16' version of the lightweight, folding A21 with all the base design work completed, but it is not yet ready. I have also done an 18.5' expedition canoe/trimaran called the XCR, which is shown. The XCR weighs-in at 175 lbs. and carries 120 sq. ft. of sail area. The first example is nearing completion in my shop and will be sailing in April.

[rapscallion]

Originally Posted by Chris Ostlind

Rapscallion,

Perhaps there is something in this collection of designs I have done in this area that might interest you?

The Fast 17 is a very quick solo or two-up boat for day sailing. It uses a rig from a an 18' beach cat of your choosing

The A18 is a two-up design meant for coastal cruising utilizing a rig from a Hobie 16.

The A21 is a two person, lightweight, folding trimaran with twin, self-supporting masts and cruising level sail area.

The Cardiff 21 utilizes a rig from an 18-20' beach cat and is a demountable design with a rapid assembly function.

The Z65 is a full-cabin, 21'4" folding tri which makes use of the hulls, rig and hardware from a 20' beach cat such a Tornado, Nacra or Hobie. This boat can be built and operational for thousands of dollars less than the L7 and especially, the long awaited F22 design from Ian Farrier. You buy a used, 20' beach cat in top condition, build the main hull and you are off sailing, long before the two boats mentioned.

There is also a planned 16' version of the lightweight, folding A21 with all the base design work completed, but it is not yet ready. I have also done an 18.5' expedition canoe/trimaran called the XCR, which is shown. The XCR weighs-in at 175 lbs. and carries 120 sq. ft. of sail area. The first example is nearing completion in my shop and will be sailing in April.

Several of these designs look interesting. The one with the hobie 16 rig looks like a good first project. I wanted my first boat to be one that I could sail with my not so able bodied wife. I'm still learning about construction methods; because I believe that will have a significant impact on my design choice.

I'm not all that impressed with the construction methods I have learned about so far; they seem labor intensive. It just seems like there should be a better, faster way of constructing a hull quickly and effectively. I have no doubt that is my inexperience talking however.

[henrikb]

Originally Posted by jamez

.............................
HenrickB your boat looks pretty cool. Are you going to offer plans at all?

Thank you

We have not considered offering plans, but if someone has genuine interest in building one, that should not be a problem!

[rapscallion]

What software did you use to design your tri?

[Chris Ostlind]

I don't know if you are asking me or Henrik, but as just a guess, it looks like Henrik uses Rhino3D from the look of the structural elements and curves present in the renderings he supplied.

I use Rhino myself.

Henrik... very nicely designed and executed hull for your trimaran project. I never tossed my opinion in the hat, but you are on the right track with your decision to go with 200% amas for the race boat. You may have to think-through the rudder solutions for this boat as I suspect you will be seriously unweighting the vaka hull when ripping-off a solid run in good wind.

Your assembly will be much easier than the comparably designed SeaCart and two reasonably healthy guys to juggle things around. This boat should be a real blast for hauling-ass day sailing. I think you'll be surprising a whole bunch of larger, fatter boats.

Please stay in touch

Chris Ostlind

[rapscallion]

Thanks for the info all. Chris O. and Henrik; Do you think an 8M trimaran with a slightly higher volume center hull (standing head room, a bunk under the cockpit) would seriously affect performance?

Chris O. Can I PM you about your Hobie design?