CR 34 prop size and pitch?

[Clay]

A question for those CR 34 owners with Yanmar 3GM30F diesel engines and three bladed fixed props..what size and pitch is your prop?

Thanks,

Clay
'89 CR 34 hull #2

[Dave Newberg]

Hi Clay,

Our Yanmar matches yours — we have a bronze fixed three blade 16x12 prop.

Sometimes the boat seems underpowered, for example when we are motoring directly into big steep seas or out of a channel with the tide, but against the incoming waves. We slow to a crawl, and it takes a very long time to recover back to hull speed. I’m not sure if that is propeller-related (to much pitch), or too little horsepower, or ???

We would like to switch to a MaxProp four or five blade. We have heard great reports from owners, but it’s always been precluded by other big-budget items.

Cheers
Dave

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[Leslie.Owen]

Thanks Dave,

We had ours repitched to 16x10 with is fine on the Chesapeake but would like to increase our speed a bit so we're not the slowest boat on the ICW trying to make the next bridge opening. I remember meeting with s/v Nood'n on their trip south at Brunswick Landing Marina he related that his CR34 with same engine can cruise at 2000 rpms and do 6 knots which I find amazing..he didn't remember what his prop size was..

We also find that in waves with short periods that we'll also stall out due to prop cavitation..

Clay
s/v Tango
Lankford Bay
Chester River, Md.

Sent from my iPad

[Dave Newberg]

I don’t have our log in front of me, but I think we get about 6 knots or a bit more at 2,300 RPM, in flat conditions of course. With that speed we burn less than 1/2 gallon fuel per hour. With a bit higher RPM we can get over 7 knots. I wouldn’t want any more pitch because it feels as if it would load the engine too much, and we couldn’t push engine RPM high enough to achieve full horsepower. That would be a carbon building situation. Even at 16x12 we need near perfect sea state to reach peak RPM, flat calm or following seas. It also helps to have less than a full forward water tank as Cigano sits a bit bow down when fully loaded.

We find that we can’t get an accurate reading with our paddle knot meter, always over in one condition/tack/current/wind, under on another, so we use the GPS for a true speed.

Cheers
Dave

[Clay]

Dave-
You make a good point about weight up forward. With a full water tank and about 275 ft. of all chain s/v Tango is a bit heavy up forward. But with a dingy and stern davits she appears to set level in the water but much lower..