Twin centerboard idea

[mrthethird]

Just kicking around an idea, looking for some input from the slightly educated or better

I am playing around with the idea of a 22' - 24' sharpie with a twin centerboard. The idea is to increase windward performance and overall stability, while keeping as shallow a draft as possible. The centerboards would be able to be set at variable depths, as well.

I got the idea from looking at some twin-keeled boats. I do not know if the idea has enough merit to pursue any farther, hence the post.

[PAR]

The number of centerboards will not increase stability, only form (shape) or weight (appropriately placed) will provide you with stability. The additional drag of the windward board (bilge board arranged) slot will not help performance much, though slot drag isn't that great. Tandem boards does offer some performance increases, but again will also have so additional drag. I've driven tandem board boats, cleating the sails and setting the boards, so you can walk away from the helm chores is nice.

[JeffM]

I've thought about twin boards, too. My cs20 can float on a "heavy dew," but not sail on one, and there are some pretty attractive shoals and river mouths I'd like to explore. I've wondered whether some sort of wide very-low-aspect fixed lee boards could be strapped on for work in very shallow water, then removed for deep water sailing. The idea went on the drawing board when the boat was still a-building, got left on the board when the boat got near the water for real.

[PAR]

I've never seen detachable fins before. The concept seems counter intuitive to me. The CS 20 can sail in thinner water then a fixed fin (twin or other wise) version. A retractable appendage is the best bet (lee, dagger or centerboard). The appendage is with the boat, doesn't have to be hauled aboard or reattached and "gunk holing" with a centerboard is a pretty easy task, using the board as a depth sounder.

Bilge keels don't have much advantage other then permitting the boat to take to bottom reasonably square. The drag typically associated with twins usually discounts there use to a fair degree. In large tidal range areas, they make a lot of sense, but a single appendage will out perform it. Climbing under the boat and reattaching the fins in a storm tossed, cold water lee shore doesn't sound like a lot of fun.