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post #3 of Old 03-07-2012
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Re: Lead 'boot' - yes/no?

Adding weight to the bottom of the keel will give you the greatest righting moment for a given weight. However, the weight will also lower your boat (i.e., raise the waterline) that much more, thus increasing the wetted surface area. As the hull moves through the water the relative contributions of wetted surface area (i.e., skin friction) and induced turbulence (i.e., form drag) change with increased speed. At low speed wetted surface area is the largest component of total drag, while at high speed turbulence increases dramatically and becomes the largest component of drag. So, by increasing the weight at the bottom of the keel you'll be increasing drag at slow speeds because you will have increased wetted surface area. But, at higher speeds the boat will heel slightly less, thus probably producing less turbulence, and be have slightly less drag (as long as you haven't added so much weight that the bottom of the transom is underwater, thus producing even more drag).

The best bet is usually to stick to the designed displacement of the hull. The designer probably put a lot of thought and effort into figuring out how much ballast was needed. Most folks (yours truly included) have more than compensated for any weight savings by accumulating all manner of junk on their boats. IF you have removed the engine, or replaced it with a much lighter one (or saved a significant amount of weight on the boat in some other fashion), THEN compensating for the difference MIGHT be appropriate. Otherwise, I would just leave it be and save your money for new sails, or somesuch.

All that being said, I used to own a boat, the Victory 21, that was built with an optional bulb on the bottom of the keel (mine had the bulb). The consensus was that V21s with the bulb were better sailers than those without. A V21 is a pretty light, pretty narrow, boat either way. My guess is that in light air the boats without a bulb would have had the edge. However, I sailed my on SF Bay, where the extra righting moment was often much desired.

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Last edited by SlowButSteady; 03-07-2012 at 06:12 PM.
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