I recently purchased a 23-foot Ahern-designed Friendship sloop and have found her to be quite overcanvassed and under-ballasted. She'll sail rail down with only 10 to 15 knots of breeze. To increase stability should I reduce weight aloft, add inside ballast, cut down
rig, or any combination of the above?
Tom Wood responds:
What you're talking about here is stability, which is a complex issue and one that is properly the province of naval architects. It involves the three things you mention above, but also displacement, draft, hull form, rig configuration, block coefficient, and a host of other considerations beyond what a few years in school would teach most of us. And they are all interrelated you can't add ballast without increasing the displacement unless you cut weight out of the hull somewhere else.
To compound the problem, there is actually more than one type of stability. Initial stability, or how much the boat heels when you step aboard, is primarily a function of hull shape. Ultimate stability, whether the boat will recover from a 90-degree or greater knockdown, is more a matter of ballast, draft, and displacement. Many boats with shallow, slack bilges heel very quickly, but then become rock solid with the rail in the water, hardly giving another degree or two in even the strongest puff of wind. I recall many hours of joyously bracing myself in the cockpit of a narrow Baltic Sea sloop that would dip its rail in 12 knots of breeze, but didn't need to be reefed unless a whole gale was blowing.
It is my opinion that many boat owners do themselves and their boats a great disservice by making alterations that should be properly left to a naval architect. The normal attempt to keep weight and windage aloft to a minimum may fall outside of this statement, but certainly chopping the rig, adding draft or ballast, making major rig alterations, changing keels, adding wings, extending rudders, lengthening bowspirits, and other major changes can have unintended consequences that spoil the sailing ability of a perfectly good boat. Besides, these modifications can be very expensive and/or time consuming, and many destroy the resale value of a stock boat. Nothing can be more disappointing than spending a good deal of effort and money on a project that doesn't end up the way we wanted. Unless you enjoy major boat projects for their sake, and don't mind the occasional vast project running amok, I'd leave the experimenting with stability issues to someone more qualified.
On a final note, what is "too tender" to one sailor may be just right for another. A Friendship is a graceful boat of long overhangs and shallow body that actually looks good at great angles of heel. If you study the old Winslow Homer paintings you will always see these vessels on their ear. Certainly, some sailor out there will appreciate all those traits and not be too concerned with her lack of initial stability. If you're looking for my suggestions, sell the Friendship to that sailor and buy a more modern design with wide beam, deep draft, firm bilges, and a long waterline. You'll both be happy and have boats you enjoy.
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