Home . Articles . News . Features . Backyard Tri

Backyard Tri

2009 August 5

High-tech but home-built is one sailor's solution to the perfect multihull

Kevin Cook sat at a picnic table in the small public park on the Galesville, Maryland, waterfront and spread out his treasures-building plans, a half-model and sections of Nomex honeycomb sandwiched between carbon fiber skins, all of which he has used to build a fast, featherweight trimaran.

The 34-foot trimaran, the latest in a variety of boats he has built in his life, is Cook's own design and a project that has absorbed more than 3,000 hours over the past four years. The aqua-colored tri has a beam of 23 feet and draws just 12 inches with the boards up and 4 feet with them down.

"I was always interested in building boats," said Cook, who is married and has two teen-aged daughters. "Ever since I was a teenager, I wanted to be a naval architect. I have built Tornados, beach cats, a Snipe and some other designs."

But rather than pursue a degree in naval architecture, Cook says, he earned "regular engineering degrees" and now is the civilian technical director for the U.S. Navy Deep Submergence Program.

What makes Cook's story interesting is that he has built the trimaran with space-age materials fabricated into mast and boom, struts and hulls largely in his back yard.

"I work with surplus materials; I get them from aerospace contractors that have leftovers," Cook said. "I made my own oven and molds (autoclaves), so I can build fairly inexpensively.

"Companies that make spars, for example, have hundreds of thousands of dollars in infrastructure. I do this in my back yard or garage and on my (gear)."

Cook said surplus half-inch Nomex honeycomb costs about 50 cents per square foot on the Internet, although there has been a shortage of materials for two or three years because so much of it has been used by the Boeing Airbus project.

Half of a 34-foot hull made from Nomex and carbon fiber skins weighs about 44 pounds, according to Cook, which makes the aqua-colored trimaran a featherweight, easily driven in light air and a missile once the breeze climbs into the teens.

"That's why racing sailors are willing to pay a fortune for this technology," Cook said, as we prepared to leave his West River mooring for a test sail.

Stepping aboard the trimaran, Cook cleared the bilge of a scant few inches of water, fired up the Yamaha outboard and began to clear away the mainsail cover and the furling lines for the jib.

"(Finishing) the cabin will be a winter project, and I'll keep it simple," Cook said, as we cast off and ran a few hundred yards out the river. "V-berth, two saloon berths, double berth aft, head and galley.

"But right now I am to the point where I can sail it and learn whether my gut feeling was right and have a little fun, too."

The breeze was well into the teens and gusting into the low 20s, and under a reefed main and a jib furled down to a sliver, the trimaran leapt onto a close reach and easily flew a hull. Cook smiled. This is what he loves and wants to share-speed under sail.

Cook says he has about $20,000 in the trimaran and has managed to buy winches, hardware and sails at bargain prices.

"But, you know, it's time consuming," Cook said. "I am sure the green boat took 3,000 hours over four years, and I really could have taken another year before it went into the water.

"But with swimming and soccer and other things, like getting the girls ready for college, you are always trying to find a spare hour or two work with the boat. I wanted to get it in the water and get some sailing time with my family this summer before there was no time."

So, Cook spent the warm weather with a gaggle of teenagers on board and learned some of the pitfalls in his manufacturing process and design. The stringers that hold the tramps between the sponsons and main hull have been stressed and cracked. The designed-in crumple zones at the bows have been crumpled and will be strengthened.

It is, Cook admitted, a work in progress.

He also insisted the trimaran can be built by any enthusiast with patience and prowess.

"I tried to make is so it is easy to build, so all the shapes are elliptic," Cook said.

"You don't have to have an engineering background. You will need a vacuum pump, plastic sheeting and a place to make a mess.

"I cooked my first parts in the kitchen oven, which, as you can imagine, caused a few problems with my wife."

But as Cook steered the trimaran through the moorage, there was a smile on his face and a mischievous bent in his manner. At 50, Cook has built another boat, and he has done it, he believes, largely on someone else's dime.

"There's a poke in the eye in that," he said. "I'm an amateur designer and builder. This proves you don't have to be rich to buy or build something modern and fast.
"This is an eBay boat. I think the only thing I bought retail is the resin."

Cook's plans and insights on how and where to purchase materials are available to anyone interested by writing to him at Cook351@verizon.net or Kevin Cook, 4522 Chestnut Lane, Rockville, MD 20853.