856-678-2186 - The online community for enthusiasts of trailerable (and cartopable) trimarans moreinfo@smalltrimarans.com

When we say, Do It Yourself Trimarans, in this post, we’re not kidding. Just recently, I was introduced to home-boatbuilder / weekly-sailor Frank Smoot. And as things turned out, meeting Frank became a real treat.

He didn’t just build 2 very low-cost small tris (for himself and his wife) — he designed them. (Not exactly an undertaking I’d recommend for most guys).

But see for yourself how things ended up.

Frank generously shares the following information (including photos and YouTube video) with us small trimaran fans. And he has even set up a website at www.DIY-tris.com to encourage others to pursue this outdoor passion … without spending a fortune.

Awesome! :-)


Do-It-Yourself Small Trimarans
by Frank B. Smoot

About two years ago, I was out cruising in the Gulf (Of Mexico) in my Kayak (a Pungo 140) a bit north of Sarasota. It’s a pretty quick boat, and I was paddling hard to catch I guy in what I later learned was a Sunfish. I was paddling my arms off, and he was just sitting there doing nothing. But I never even got close to him, so I thought,”What’s wrong with this picture.”

My wife, Laura, also had a Pungo 140 kayak, and I thought it might be cool to try and make a catamaran out of them, and rig a sail and rudder to it. It was, at best, a poor sailboat — especially because, at the time, I had no clue about CE (center of effort), CLR (center of lateral resistence), and the other important stuff you need to know to make a sailboat go where you want it to go.

I should mention that there was another BIG inspiration for going multihull. Laura and I briefly (very briefly) owned a Laser II, an old but quick and nimble monohull designed back in the ’70s. Since we knew next to nothing about sailing, we dumped it within the first 30 minutes of sailing it.

This was pretty traumatic, not to mention embarrassing. And since we’re both over 60, we decided that very day we wanted to “sail flat.” So I set out to build my first non-kayak-based catamaran. (Long story there, including snapping off a wooden mast like it was a toothpick.) It was a real dog to sail, but a great learning experience!

I am a cheapskate by nature, and I spent much of my working life as a remodeling contractor. I always use the least expensive materials that will produce a quality job. I kept hearing about “marine plywood” and “okume” and all that stuff, but I thought the price was ridiculous. And besides, nothing I built at that point was probably going to be worth keeping long enough to worry about rot :)

What really got us both into trimarans was when we rigged up sails, rudders, and outriggers to our Pungos. Crude, but amazingly effective. If you really want to learn about tris, cheap and quick, get an old kayak and rig it to sail.

I have now built about 10 different boats, the first several being catamarans, and all the recent ones being tris. The two latest ones (including the one in the video) are 16′ long, very narrow, and are much quicker, smoother, and drier than anything I built before. They also tack and point very well.

Frank's DIY Trimaran Under Construction

DIY Trimaran's Amas Half-Built

First, I built one for me, than another, lighter one for Laura. They have very different hull shapes, since everything I built is intended as a test-bed as well as a pleasure boat. Mine has gone 13 mph with just a single 84 sq. ft. sail on an unstayed, home-brew mast. Her boat is probably as quick, and was going at least 11 mph when she shot the video — with both hands free, I might add.

Our local bay gets very rough when the wind is westerly, and that interferes with both enjoyment and boat speed. So we like to sail most when the wind is at least 7-8 mph or more, up to about 15 mph, and not from the west.

Tortured Plywood Trimaran Amas

DIY Trimaran Boat Seat

Probably my favorite current story is when the video (shown below) was shot, just about a week ago. I forgot to bring the Garmin with the GPS, so our speeds are just estimated. But since I sail both of our tris several times every week, I’m good at estimating speed now. That day, the wind was northwesterly at 8-12 mph, so the waves were smallish and we could go fast without getting wet.

DIY Trimaran with 84-Sq Ft of Sail (Pre-Leeboards)

DIY Trimaran with Laser II Rig

Her hull is essentially flat on the very bottom, where mine is a V-hull. I had thought mine would be quicker, but hers planes very easily and goes faster with less sail. On that day, her tri was running our 84 sq. ft. sail, and I had just set my boat up to run the Laser II rig (124 sq. ft. with main and jib) that you see in the video. My mainsail was 89 sq. ft., and on that alone, I couldn’t catch her boat. (She’s an excellent, very intuitive sailor.)

Laura's DIY Trimaran is Slicker n' Quicker

DIY Trimarans on Trailer

Only when I put up the jib was my boat faster. And even with my full rig, I couldn’t catch her running downwind. On balance, we have concluded that a single, unstayed mast with a sail in the 80-90 sq. ft. range is perfect for these little boats. The much bigger Laser II rig is quicker, to be sure, especially close hauled. But it’s much more of a hassle to set up, and makes the boat lean more because the shrouds needed to be attached to the amas (outriggers). Plus, you have to tend two sails. Bottom line: one sail on one unstayed mast = best bang for the buck!

Laura's DIY Trimaran (w 84 Sq. Ft. of Sail)

My biggest regret is that I didn’t start doing this years ago! Of course, I also didn’t live in FL until about 4 years ago. This area is small sailboat heaven … as long as you can deal with some very shallow water now and then (another major factor influencing my designs).

I can sail 12 months of the year down here, as long as I can keep from getting splashed too much in Dec-Feb. That’s why my boats have lots more freeboard than our kayaks. Laura loves to sail, but maybe once a week. I’m a true “tri-junkie,” and have been known to take a boat out every day. Of course, being just 10 minutes away from a beach launch point is a big help. But I’d find a way no matter where I lived. When the wind is right, there’s just nothing like a small tri. Cleat the mainsheet, steer with your feet, and your hands — and spirit — are instantly free!

I’m planning lots of articles about what I’ve learned and done (and what I’ll do in the future) at www.DIY-tris.com. I want to spread the word to others, and help inspire them to build and sail small tris!