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Old 04-11-2013
bobperry bobperry is offline
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Re: Modern Hull forms and Motion Comfort

I agree Jeff on the SA/D aspect of the added weight. But and this is a big but, I still think the lighter boat will be the better performer. One number doesn't tell the entire story. Remember the lighter boat in all probablity would have started with a much higher SA/D to begin with. Your typcal D/L 250 cruiser would probably have a SA/D around 17.00before loading. While the lighter boat most probably would have SA/D around 20.00 and maybe even higher before loading. Add the extra weight and the light boat in almost all cases would still have a higher SA/D or at the least the same SA/D as the heavier boat.

Let's do the math:
A 24,000 lb. boat with 850 sq. ft. of sail area (Valiant 40 specs) will have a SA/D of 16.34 prior to loading.
Load on 2,700 lbs. of gear and the SA/D drops to 15.22

A 14,000 lb. modern boat with 800 sq. ft. of SA will have a SA/D of 22.00 prior to loading.
Add the 2,700 lbs. of gear and the SA/D drops to 19.59.

Even if I cut the rig down on the light boat to 700 sq. ft the loaded SA/D is still 17.1.
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Last edited by bobperry; 04-11-2013 at 12:58 PM.
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