JoL-Trimaran Project

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Design Challenge
by Cristian Pilo ...

as a sailor, before being a boat designer, I always loved multihulls. I learnt the first elements of sailing on Hobie 16, terribly fast, easy, 4 control lines on the whole boat. After transitioning to monohull dinghies, I regained the same thrill for speed only a couple of years later sailing on my friend’s skiff, a ISO Topper. When I became a boat designer, I kept on studying the multihull world, with a main focus on cruising “foldable” trimarans like Farriers.
The thing that mostly amazed me was the capability of going fast, rocket fast compared to a same sized monohull, while keeping the cruising aspect of the boat. In a 33 footer cruising monohull you live in a world of single digit speed, 10 knots are a dream that you can only achieve for short thrilling moments while surfing down a wave in 20 knots of wind, 6 knots is your average speed, 140 nautical miles in a stretch of 24 hours sailing are a very good achievement. Cruising Tris live in a different realm, they unveil new possibilities of cruising, while you easily cruise at 12 knots and you can plan your weekly sailing adventures in a radius of 300 miles and more from your launching marina. And most of all you can sail in light wind keeping a decent pace, when you would be forced to motor in a heavy cruising monohull, or get stucked.
So, when Miloš and Kerstin asked me to design their new boat, a cruising trimaran, I jumped on the project with the enthusiasm of a boat designer that longed to be involved in a similar project for years, but was conscious that investing the huge amount of time required to design a similar boat had no sense without having a committed boatbuilder; I took advantage of tons of sketches, ideas, conversations with sailors, and of all the time I spent in the last 15 years studying this kind of boats. So the design process was quite smooth and we reached a good design stage in few months.
Without digging too much into technical aspects, there are several concepts which makes designing a trimaran a whole different world compared to designing monohulls, which is what I normally do.

• The ballast keel is missing, you only have a Daggerboard, so all the strong structures which are made to avoid the keel from being eradicated, literally, from a heeling hull, can be dismissed or greatly reduced. You do not have to cope with a ton of lead hanging 2 meters under the boat with all his rocking, pitching and yawing. The whole structural scheme for a Tri is totally different form a monohull, so you need to think differently and understand where to put your reinforcement elements and how to size them properly.
• The boat heel far less than a monohull, but you have a super powerful boat. That means a HUGE amount of righting moment given by the total beam; this means that all the structures that keep the boat, amas and central hull, together, have to be designed and built bullet proof strong. This is where Miloš’ skills in building under vacuum with carbon fibers, skills developed with Alcedo rig, come into play, because I felt free to design full composite crossbeams being sure that they will be build at the state of the art.
• Trimarans, an esoteric field: I have a decent experience in monohull design and in any case I can rely on a very solid literature on the subject; Tri world is quite different, there are few boatyards producing boats in good numbers, there is a kind of “try and modify” approach on a lot of builders, and a subtle obsession for feather light boats is quite common, sometimes on the edge of structural integrity. All these factors made it not so easy to get a reliable feedback on structural aspects. I had to dig a lot, and crunch a lot of numbers. JoL will be a cruising trimaran so I was not obsessed by weight savings, and this aspect took me to some “conservative“ choices in terms of structural scantligs. JoL will not be a feather light rocket, but she will be fast, strong and safe, and these are the main points we focused on, both me as a designer and Miloš and Kerstin as boatbuilders.

So here we are, boat building process is officially started with the floats a couple of weeks ago, the amas in trimarans slang. I am refining the last details in 3D CAD for the central hull and rig, and then every building detail will be transferred to the building plans, and Miloš and Kerstin will be ready to pass from a bunch of paper sheet to a fast affordable sailing boat. Given the awesome work they did with Idea21 - Alcedo, I am 100% sure that JoL will be a wooden wonder too.

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