Picture of 24 foot Sailing Trimaran
Indonesian style, built out of recycled stuff.
Here we are busting out through the surf in 30mph winds at Stinson Beach California on the maiden voyage. The boat works great! There are no swimmers or surfers out because of the rough conditions. The kids are on the beach making forts out of their boogieboards instead of surfing.

Hull Length 24 ft at deck
Hull 22" wide amidships at deck, 18" wide inside hull (there's a wide lip at deck)
Hull 24" deep amidsnips. The hull round bottom is a semicircular arc of 8.25" radius.
Hull rocker is about 4" measured from points 16' apart.
Outrigger crossbeams are 14' 7" long 3.5"x2.5" fir beams tapering to 3x2.25" at ends
The outrigger floats are 4.5" diameter, 19 feet long with foam plugs in ends. ~134lbs buoyant.
The plugs in the front of the floats are shaped into a nose that protrudes 6.5" more.
1.5" diameter stainless steel tubing connects the crossbeams and floats.
The Sail is an 8 sq. meter crabclaw / leg-o-mutton sail on 14ft. windsurfer masts.
The mast is supported by three stainless steel cable stays.

Total cost of materials was $200 or less.
The outrigger floats are fiberglass chemical pipes full of empty plastic soda bottles.
The main hull is made from a pair of old 16' catamaran hulls cutoff and glassed end-to-end.
Junked catamaran hulls are easy to get. If you can't find a free hull, build a hull like the Kenya Canoe but bigger. Use scavenged plywood from crates if you want it free.
The wood for the crossbeams came from a big pallet, with the nails and crossboards pulled off. Then I scarfed them together for extra length.
The sail is blue tarp on windsurfer mast spars.

Great action photos by kenny
ilpug3 years ago
As usual, awesome instructable. Your how-tos seem to be more like stories than instructions. Except for the *innocently scrolling, then: Oops, naked dudes hot tubbing* moment, awesome! Not really minding the hot tub thing, just kind of a surprise :P
big len5 years ago
What kind of decking is that.....and how is it attached?  I can not tell from the photos how the seating is arranged.  Are you sitting on top or in?

This is fantastic by the way!  I was just looking into building a outrigger out of a hobie 16 hull and a pvc pipe as an aka.

Thanks for your great instructables
ANDY!6 years ago
sweet boat. im making a boat like that.small one for lakes
Pkranger886 years ago
Did you just post a photo of naked dudes in a hot spring? Ahhhh, Tim and I like your ibles so much....Then you gotta go ruin it for me.
Looks like they deliberately posed so as to avoid it being adult. Wouldn't be a good 'ible without at least one "what the heck?" moment.
Still...is it weird that I was thinking...Awe, man I'm looking at a photo of naked dudes. There's just something wrong about that.
Wade Tarzia6 years ago
Nice! I suggest one improvement: retitle to How to Improve a Catamaran :-)
Ferrite6 years ago
That Cuba story is amazing!
joe karr6 years ago
Hey, thats sailing! launch from the beach, exceptional prototyping. The kayak I was coating... is christened and is an excellent bay boat, on to the surf Umiak.. any input to design appreciated Joe / bohemianblacksmith@gmail
TimAnderson (author)  joe karr6 years ago
Here's my umiak.
If I made another one I'd raise the sheer at the ends more.
All that rocker makes it pretty impervious to waves, but the compounding in the shape makes it hard to cover with a single sheet of cloth. Notice the wrinkles when we put a heavier skin on it.
Oars are nice. Have you seen the currach rowing in "Man of Aran"?
You had a bit of pornography in step 12, might wanna block it out, and you said "on" twice in step one. Nice instructable though.
TimAnderson (author)  Yerboogieman6 years ago
It's all pornography! :) thanks!
Yeah, but know there will be that one parent that will say the classic "This is a family-based website." And you are very welcome.
Sweet! two-hundred instructables!