Prop Replacement

[Steve Files]

I have a CD 27 with a 2GM and am presently considering replaceing the two blade 12x13 with a three blade 13x12. I'm interested in anyone who has had experience going from a two to three blade.
I think this should be a good up-grade, but I"ll have to do a little re-working of the aperture to fit the prop.
Any info about the subject would be appreciated.
Thanks.

Steve



Steveskipr@aol.com

[sam]

several prop companies have web pages and for a small fee you can use a program they have to determine the best prop for your boat. I don't recall the names now but I found them by searching Yahoo etc for props, prop shafts. Think one was proper pitch. I bought a new prop shaft from the one in Fl. Very happy with it and the service. Sales man was helpful delivery was fast price was fair.

[Tom]

I have a CD 27 with a 2GM and am presently considering replaceing the two blade 12x13 with a three blade 13x12. I'm interested in anyone who has had experience going from a two to three blade.
I think this should be a good up-grade, but I"ll have to do a little re-working of the aperture to fit the prop.
Any info about the subject would be appreciated.
Thanks.

Steve

I don't have your engine so can't give an opinion about the diameter and pitch you propose, but I switched from a 2 blade to a 3 blade. It makes a really noticable difference all to the good. I would never consider going back. I think you'll be pleased. Before you go up to a larger diameter and mess with the aperture, why not switch to a three blade of the same diameter and see if it won't do you. My experience is that a three blade switch gives you noticeable improvement whereas an inch in diameter is hardly noticeable. Be careful not to over prop the engine as this can cause ring wear and ultimately damage the engine. Your prop shop can probably advise you on diameters and pitches.



TacCambria@thegrid.net

[Lyn Heiges]

I have a CD 27 with a 2GM and am presently considering replaceing the two blade 12x13 with a three blade 13x12. I'm interested in anyone who has had experience going from a two to three blade.
I think this should be a good up-grade, but I"ll have to do a little re-working of the aperture to fit the prop.
Any info about the subject would be appreciated.
Thanks.

Steve

I have a CD27 (GUILLEMOT #186) which has the original Yanmar YSM-8 with the two-bladed prop. I IS MARGINAL!!! In 1982 they upgraded to the Yanmar YSM-12 and kept the two-bladed prop. WHY? I don't really know except that for the more "pure at heart" the two-blade design can be rotated so as to be in line with keel and reduce drag. This is reality, but how many of us really ever do it? I marked my shaft with a couple of white lines and did it a couple of times, but that was it. I now also have a CD28 (MOON CHILD #307) which has been retrofitted with the Yanmar 2GM20F and a 13 X 13 three-bladed bronze prop. WHAT A DIFFERENCE!! It is almost as good as my Grady-White with a 200 HP Merury Black Max and 14 X 19 three-bladed prop!

I think the performance is just as good (except for the "purest") and I am never going to win a race with CD, but at least I know I'll get there in one piece, so Hail! to the three-bladed prop.

Lyn



lheiges@compuserve.com

[stephen sousa]

several prop companies have web pages and for a small fee you can use a program they have to determine the best prop for your boat. I don't recall the names now but I found them by searching Yahoo etc for props, prop shafts. Think one was proper pitch. I bought a new prop shaft from the one in Fl. Very happy with it and the service. Sales man was helpful delivery was fast price was fair.

I have gone through the same exercise with the Alberg 30 running a 2GM20F. The original prop was a 12X11 2 blade which I am replacing with a 13X13. The propellar analysis completed on the Alberg recommended a 13X13 machine pitch. I wanted to be on the conservative side the replacement is a sail prop vs.machine pitch. I have sailed on a Dickerson 36 with a 3 blade, she runs at 1800 r.p.m. pushing 6.5 knots. I am sure you will be satisfied.