Join Date: May 2002
Thanked 28 Times in 26 Posts
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Thank you all for your very informative responses.
Jeff H., you said: "The waterline length is thought to limit the hull speed because if the boat goes any faster the stern wave has to move further back taking the trough between it and the bow wave along with it. As the trough moves aft, it causes the stern to drop, making the boat sail uphill…[A] boat with extra volume in the stern can exceed its theoretical hull speed because the extra bouyancy prevents the stern from dropping into the trough." That seems to suggest that you should move crew weight forward whenever the boat is nearing hull speed. By doing so, you lift the stern slightly, making the boat ride in the water as if it has more buoyancy in the stern, and deterring the stern from dropping into the trough. Is that correct, or am I missing something?
In the materials submitted by Duane, the author says, "The formulas show that lower displacements permit higher speeds without actually planing." That really puzzles me, because if the speed of a displacement boat is limited by the fact that it can only climb up over its own bow wave when it is planing, then logically it seems that the only way that the boat could go faster without planing is if the bow wave itself moves faster through the water. So, does anyone know if the bow wave of a light displacement boat (which is presumably smaller than the bow wave of a heavy displacement boat of the same length) moves faster through the water than the bow wave of a heavy displacement boat? Or, is there some other explanation that I am missing?