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Old 02-07-2014, 07:28 PM   #36
Tad Roberts
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Quote:
Originally Posted by sunchaser View Post

How would describe your PL designs in light of this discussion?
Oh boy...are you sure you want to incite this? I'm not at all interested in making any sales pitch but I'm happy to try and shed some light on questions of naval architecture.

The PL (Passagemaker Lite) design, like Dashew's FPB, the Vripack Ned, and Nigel Irens LDL designs, is a "High-speed" displacement hull. It's ratios, shape, and performance are similar to a naval Frigate. Somewhere between a Frigate and a high-speed displacement catamaran. A lot faster than typical heavy "Full" displacement hulls, these hulls achieve speed by being small (in cross section), relatively high-powered, and light weight for their length. Unlike a semi-displacement hull, they are not intended to lift with speed at all. Rather the idea is to reduce wetted surface and wave-making to allow the hull to slip along at higher speed. They lack the bottom area to get any useful dynamic lift as big wide (and usually heavy) semi-displacement boats do.

You might find some reference to this in the Dave Gerr link above. He couples it to displacement/length ratio. The lighter (displacement) a hull is for a given length, the higher it's "Hull Speed" will be.
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