Bruce Roberts is releasing a new series of Sailing Cruising Catamarans. These tips should help you to evaluate that catamaran you are considering building or buying.
Catamarans - 2 Hulls Of Fun.
I’ve been asked many times in my career, "What kind of boat I would have if I could have any kind of boat"? My response has been a "Sailing Catamaran” without hesitation. Don’t get me wrong, I love sailing a monohull, especially to windward, but for all around cruising fun, I would choose a catamaran. They are quick, stable and provide a wonderful platform from which to explore and enjoy the watery world we all love.
The Weight:
It’s not all sweetness and light with a catamaran however; just like all boats there are compromises and parameters to remember when choosing the right boat to suit your requirements. A catamaran platform gets it high speed potential from the slenderness of its hulls. The ratio of the length of the hull to the beam of the hull describes slenderness, and in general, the higher the slenderness, the more slippery the hull. Unfortunately, slenderness comes at the price of load carrying capacity – meaning that hulls with high slenderness values simply cannot accommodate as much weight. This fact needs to be kept in mind when selecting a particular boat to build. If one wants a “high performance” catamaran, capable of speeds in the high teens/low 20’s, then the building material needs to be lightweight, such as foam cored fiberglass. In addition, special attention needs to be paid to what will be carried on board and what equipment will be used. One cannot have a “high performance” catamaran and expect to carry hundreds of gallons of fuel.
A Heavy Issue:
The sensitivity to weight in a cat design is one reason we at Bruce Roberts do not suggest building a small to medium catamaran in steel. The boat will simply not perform as expected. Once the size of the boat exceeds 65’, steel can be considered for a power cat or a motorsailing cat, but below that size aluminum, fiberglass or wood must be used. Overloading in a catamaran, either due to carrying too much "stuff", or due to selecting a hull form that is too slender for the use intended, can result in a variety of issues. These issues include increased draft, reduced wet deck clearance, reduction in speed performance and overstressing the sailing gear (if it’s a sailing cat).
The easiest way to avoid overloading the boat once its complete is to choose a boat with a reasonable weight for its size. A 50’ cat to be built in aluminum cannot weigh 30,000 lbs, and if the boat has been designed for that displacement, consider another design that is better suited to aluminum. At Bruce Roberts, we design our catamarans to have enough buoyancy in the hulls to accommodate the materials specified in their build and to have a reasonable carrying capacity.
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