Prop needed!

Hello all, I need some advice. Last weekend I noticed a lot of vibration at around 2000 rpm on the way out to sea. The following day while the boat was getting cleaned, the diver informed me that my prop was cracked. He asked me if I hit anything?!?! That wasn't the case so I just had a look for myself and the prop is indeed broken. The boat is a Ericson 46 (1972) with a 3 blade self feathering prop (or variable pitch?). One of the blades is broken in half. Can someone tell me what brand/type/size prop I need to replace this? Any help would be greatly appreciated!
Thanks,
Johnnyb

I my experience, (if it is indeed a feathering prop) both Martec and PYI offer excellent service to customers needing a prop rebuild.
IIRC, they have supplied the lion's share of feathering props in this country for several decades.....

If that prop is one of theirs, give them a call.
Loren

johnnyb said:

Hello all, I need some advice. Last weekend I noticed a lot of vibration at around 2000 rpm on the way out to sea. The following day while the boat was getting cleaned, the diver informed me that my prop was cracked. He asked me if I hit anything?!?! That wasn't the case so I just had a look for myself and the prop is indeed broken. The boat is a Ericson 46 (1972) with a 3 blade self feathering prop (or variable pitch?). One of the blades is broken in half. Can someone tell me what brand/type/size prop I need to replace this? Any help would be greatly appreciated!
Thanks,
Johnnyb

Click to expand...

Johnny,
It is impossible to answer your question from the information given. That's because in order to know the correct pitch for a prop (for a given diameter and number of blades) one would have to know both the engine hp as well as the transmission gear ratio.

Another E46 owner *might* be able to give you the right info, assuming: (1) his/her boat has the identical engine and transmission as yours; and (2) the prop on that boat was correct to begin with. Regarding that second point, boat builders not infrequently slap on the wrong prop (or a PO may have) so one should not assume that it is correct even if the prop was factory installed. Now would be a good time to make sure you get a prop with the correct specs.

Fortunately, any good prop shop should be able to set you up. Loren's suggestion to contact Martec or PYI is good. I've never dealt with PYI but on my previous boat I had a 2-blade Martec folder and their customer service is excellent. Here is what they'll need to know: (1) Engine hp. (2) transmission gear ratio. (3) The number of blades you want. (4) The diameter you want.

Regarding the diameter, that is going to be limited by the hull clearance, among other things. Most likely your existing prop was fine diameter-wise, so getting the diameter off the existing prop is probably all you need to do. You or your diver can readily determine this from the remaining blades.

Did your diver recognize the brand by seeing it? I'm wondering if a single blade of your brand (whatever it is) is replaceable. If so, it may be less expensive to try that route. If not, a search of prop discussions on this site will supply lots of useful pros and cons of prop replacement. The folding & feathering types are great but expensive; probably the least expensive feathering type is a Kiwi Prop. I have one on my E-38 and love it. The fixed types are more economical, and a Campbell Sailor is probably the lowest drag of those types; but do check out the other discussions here on this topic. Good luck!