2 versus 3 bladed prop for CD33

[Frank Vernet]

Hi Everyone

I'm mulling over the idea of replacing the original (read - 1982) 2 bladed prop with a 3 bladed prop. I'm hoping to get a bit more efficiency and speed from the 3-bladed prop. Has anyone done this or researched it? I have a 1982 CD330 w/ a 3 cyl 24HP Universal Atomic (#30, Model 5424) and a 2:1 transmission ratio. Please advise. THKS

Frank



vernetf@afwtf.navy.mil

[Clay Stalker]

Frank,
The previous owner of my CD27 replaced the original (also 1982) 2-bladed prop with a bronze 3-bladed and was very pleased. I have never sailed the boat yet, so can't comment from personal experience. But he told me it improved speed while motoring, improved backing down (which is not good in these boats) and he didn't notice a huge difference in sailing speed. It doesn't seem as though it would be a good idea if racing or getting places fast is important to you...otherwise, it might be. Others on this site will surely have some other opinions...good luck, Clay

Hi Everyone

I'm mulling over the idea of replacing the original (read - 1982) 2 bladed prop with a 3 bladed prop. I'm hoping to get a bit more efficiency and speed from the 3-bladed prop. Has anyone done this or researched it? I have a 1982 CD330 w/ a 3 cyl 24HP Universal Atomic (#30, Model 5424) and a 2:1 transmission ratio. Please advise. THKS

Frank

cstalker@cheshire.net

[larry M]

Frank,

I have a 3 bladed prop on my CD33 with a westerbeak 27hp. From a cruise point when motoring in calm seas I run at 5.5 to 6 knots and burn .4 gal per hour. One thing I have noticed over two bladed props is that you can stop forward movement very fast. I am not sure but am inclinded to think the 3 blade walks more though.
Larry

Hi Everyone

I'm mulling over the idea of replacing the original (read - 1982) 2 bladed prop with a 3 bladed prop. I'm hoping to get a bit more efficiency and speed from the 3-bladed prop. Has anyone done this or researched it? I have a 1982 CD330 w/ a 3 cyl 24HP Universal Atomic (#30, Model 5424) and a 2:1 transmission ratio. Please advise. THKS

Frank

lmace@gt.com

[mike]

Frank,

I put a michigan 3 blade on my cd33 last year before I left for a roundtrip from lake ontario to the bahamas and back.

best thing i ever did. gave the boat a whole lot of control, didn't seem to effect boat speed, sure it did though, gave LaVida more punch when heading into the Gulf Stream seas.

Only downside i noticed is that with the two blade my shaft would turn some of the times, now it turns all the time.

I would recommend the conversion. Michigan wheel offers free spec service from their nautical engineer.

sea u,
mike



mpr@seascan.com

[Al Smith]

Frank,
The previous owner of my CD27 replaced the original (also 1982) 2-bladed prop with a bronze 3-bladed and was very pleased. I have never sailed the boat yet, so can't comment from personal experience. But he told me it improved speed while motoring, improved backing down (which is not good in these boats) and he didn't notice a huge difference in sailing speed. It doesn't seem as though it would be a good idea if racing or getting places fast is important to you...otherwise, it might be. Others on this site will surely have some other opinions...good luck, Clay

Hi Everyone

I'm mulling over the idea of replacing the original (read - 1982) 2 bladed prop with a 3 bladed prop. I'm hoping to get a bit more efficiency and speed from the 3-bladed prop. Has anyone done this or researched it? I have a 1982 CD330 w/ a 3 cyl 24HP Universal Atomic (#30, Model 5424) and a 2:1 transmission ratio. Please advise. THKS

Frank
I have replaced the three blade prop on my '84 CD33 with a 2 blade and lost speed and power. But it did drastically cut down on the cavitation noise I heard. I've since gone to a Campbell Sailor's prop and have regained the power and speed without the cavitation. One other effect, almost no prop walk. I know that has its good points, but it can be annoying, too.




Saylr@mindspring.com

[Glen]

Al,
Can you comment on your experience in obtaining your Campbell Sailor prop? Did they properly size/pitch the prop for you from your boat specs or did you have to make adjustments? Do you have the size/pitch on the old 3 blade prop and the new one? Other than the lack of cavitation and prop walk, any other gain in performance? If you had it to do over, would you still buy the Campbell prop?

I've repowered my CD30 with a new Yanmar 2GM20FV and have been looking at new props...with my eye on a Campbell Sailor, but the only other comment in the CD archives is not postitive in dealing with the company.

I have replaced the three blade prop on my '84 CD33 with a 2 blade and lost speed and power. But it did drastically cut down on the cavitation noise I heard. I've since gone to a Campbell Sailor's prop and have regained the power and speed without the cavitation. One other effect, almost no prop walk. I know that has its good points, but it can be annoying, too.

glen@cambio.acomp.usf.edu

[Joe Valinoti]

In regard to the 2/3 blade. Just remember that PHRF gives you an extra 3 seconds per mile if you have a 3 blade. Obviosly there is a difference. My CD30 with the 3 blade is no match for my CD28 with a 2 blade. You can't lock the 3 blade in the aperture for no drag.
Joe



vwman@coastalnet.com