still on the hard

[Thad Gilder]

Still drying on the hard. Need to finish some projects quickly as hull will be ready for patch and paint soon (I hope). First, does anyone have the size and pitch of the original prop for a Yanmar 2GM 13? Mine has a 13x10 3 blade and I have notes in the original owner's manual describing the purchase of that blade (note reads "decrease diameter by 2 inches when converting to 3 blade cruising prop"). I want to go back to a low-drag sail prop, and yes I understand the loss of power, etc., but I'm sailing on a small lake. I've got a Beneteau First 29 and a Pearson 30 to keep up with, and I don't want to invest in a folding prop. And, yes, I've checked the archives and haven't been able to find the original size.Second, there is a cutout in the top third of the mast for an exit block. Opening is 2 7/8 x 3/4, bolt holes are 1 7/8 x 1 1/2. Does anyone know the original manufacturer of this block or suitable replacement? Thanks for your help, folks.

 

[Pat McCartin]

Thad..

My '79 H30 had a 13x13 two blade prop with a 2QM15.Pat

 

[Ed Allen]

gear ratio

To give you a good size one would have to know what gear ratio your engine is. Any yanmar dealer can help you or you can use a prop size calculator to get you in the ball park. there are several on the net, just look around on the propelor sites. the engine rpm and the gear ratio of the transmission are what you will need off of the boat. There are 3 different ratios available on that engine.

 

[Ed Schenck]

Ante up!

Buy a folder and make the other guys try to catch up. It really does make that much difference. Call Flex-O-Fold, he will give you the right pitch/diameter info and a price that is very reasonable.If you do not like his price you will still have the right numbers. Then look for a used folder. There was one in my marina the other day for about $20. Perfectly adequate for getting out to the race course.Watch E-Bay, there is a folding Martec on there right now but too small for you.

 

[J. Tesoriero]

How does your boat perform?

If you an get near hull speed (~6.0 knots) with your current prop with the engine at cruising RPM's (85% of max)with a clean hull etc, then you have approximately the correct size and pitch for your three blade. Then the conventional wisdom says it is OK to increase the pitch by 2 inches when you go from a 3-blade to a 2-bladed prop. If you are not getting hull speed and/or are experiencing smoking, overheating or other such signs, it is best to consult several of the prop manufacturers for their recommendation on the best prop specs for your application.As for your mast, some Hunter Spars for that period were made by Kenyon, Inc. now a subdivision of Sparcraft (Isomat), Inc. A few years back they were at 1031 Amble Drive, Charlotte, NC 28206: 704-596-9449 Ext. 308, ask for Rusty Privette if he is still there. They have some stock of replacement parts for the mast and boom, including sheaves.

 

[Thad Gilder]

Thanks Folks!

My mechanic and I pulled the shaft today and it looks like it needs to be refurbed or replaced - had some electrolysis damage, otherwise it was true to 1,000/inch. We also agreed we need to replace the mounts. Then the yard manager showed up and announced that the folks who ground out my blisters went too deep - so now I'm looking at fiberglass filling rather than epoxy or resin. Looks like spring for the new launch date, so maybe I can find a used folding prop. I sent a request for information to Flex-o-Fold today and will try to contact Gori next week. And thanks for straightening me out about the pitch increase rather than diameter - I was about to really goof up.... Ever heard the saying about a boat being a hole in the water...