Catalina 30 Motoring Speed

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Ethan

i have a catalina 30, with a atomic 4, that motors at 4.5 knots max. my friends sailboats motor at 5-6 knots. they have longer boats, with larger keels, but with less horsepower. i thought it was all the gear i had for cruising but now that it is off it is still maxing out at 4.5 knots. under sail the speed is fine, but id like to be able to keep up when motoring. i think it may be the prop, but what should i buy...there are too many choices??? any help would be appreciated.
 
Dec 2, 2003
392
Catalina 350 Seattle
Clean Bottom First

Ethan - all things being equal, check to make sure that you have a clean bottom - if you have a ton of slime or other growth, you are going to be slower. Your hull speed in the 30 should approach 6.8 knots or so, a boat with a longer waterline length - like your buddy's, should be faster - inspite of the horsepower. You are right on to look at the possibility that you are carrying too much weight - but if you've taken care of that, then maybe the bottom. Other things to think about - before you go experimenting with props - are you sure that you are accurately gauging that you only do 4.5? Is it possible that your knotmeter is out of calibration? Check your speed with a GPS or against some of the measured mile courses around. Is your engine making full RPM's? It always makes me wonder when I read posts from people that want to change their props, I'd never even considered that the prop that the builder put on the boat wouldn't be the right one to have on there. I guess things can be changed over time, but the volume of people on message boards that ask those types of questions amaze me. I've even thought about starting a topic about that very subject. Anyway, check out the easy/cheap things to address first, then consult a professional before you think about changing props. Good Luck - looking for some of that elusive spring weather in Seattle soon! Tim Brogan April IV C350 #68 Seattle
 
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Ethan

Thanks for the reply Tim. I did all my testing with a freshly cleaned bottom, using a GPS, and without a current/wind. The only thing I can think of is either the motor isn't making maximum RPM or the prop is hindering the engine performance. I will make sure the engine is making maximum RPM before I spend the money on a prop. Thanks again Ethan
 
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