Folding props

[msenko]

What is the size of the props used on the Catalina 34? Specifically, mine is a 1987 model with the 21 hp engine.

With the fixed prop, what is the maximum rpm's you are able to get from the engine, and what is the cruising rpm's and speed you run at?

I want to purchase a Martec folding prop for mine, and don't know what size to buy.

Thanks

[dave davis]

Mike, My 1988 boat came from the factory with a 15/10 fix prop. Because I race, I changed it to a 15/13 Martec back in 1989 and it's been that way ever since. After years of use, I had it reworked by a prop shop a few years ago. With a clean bottom and smooth water with no wind I can get 6 knots at 2000 rpm. I usually cruise at 2000-2200 rpm which give me 5.5-6 knots in normal seas and wind. To answer your question about about how high the rpm's can go if I pushed it all the way(which I hardly ever do), I can get about 2800 in gear. :)

[msenko]

Thanks for the input. It sounds to me like your 15X13 folding prop is just about the right diameter and pitch for a C34. All of the boats I have owned have all run at about 2800 rpm's at WOT, and cruise was around 2000 rpm's or least vibration.

Is your know meter calibrated? Do you use GPS to get your speeds?

[dave davis]

You're correct Mike, I failed to say that my knot meter has not been calibrated but its usually   pretty close to other boats when we check each other. My tach seems to be reading lower than other boats when side by side. I shoud get a meter and check it out. We seem to have current most of the time, so my GPS is either too slow or too fast. Maybe I'll try to take the time to find a slack current time and check it out vs the knot meter.