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post #5 of Old 03-11-2005
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propeller size

Your boat is popular and well known in the industry. If you call any reputable prop shop (be sure they have the computer program) and give them your boats displacement, horsepower & RPM, waterline and beam, etc., etc. Just be ready for a flurry of questions. Also, you might need clearance for the blade tip. Sometimes the computer kicks out a size that doesn''t leave the 10% tip clearance required. My boat works GREAT with a 20" prop, but throbs like hippos humping. An 18" does the trick.

Sometimes I call five or six different prop shops for a customer if his boat is rare, like a wooden Bahamian Sloop, to see if 3 out of six land on the same numbers. That gives me confidence.

Also, don''t be shy about pressing your own preferences. For instance, my engine can rev to 5400 rpm, but I VASTLY like the sound of it better at 1500 to 2000, and it has plenty of power there. The first time I let a prop shop give me what they wanted, the 18" x 11" prop they supplied had my engine spinning giddy and still not performing well (I think it might have been cavitating from over revs). I took it off and went to a 16" x 16" I had hanging around and that worked fine, though a bit tall (some funny docking stories). An 18" x 14" works great.

By the way, my boat is a heavyweight like yours, but 33'' x 12'' with 22,000 lbs and 52 horsepower. Different critter, prop-wise.
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