New Prop for CD36

[Troy Scott]

Folks,

I know several of you have experimented with various propellers on your CD36s. The manual states that the boat was originally equipped with a 15-14 prop. I have the Perkins 4-108 engine. I have a 15-14 prop now, but it has a dubious past. I'd like to launch the boat with a new prop. A Campbell Sailor has been recommended to me. I'd like to know what experience, pro and con, that you all have had with Campbell Sailor props. I'd also like to get recommendations WRT pitch. I've read the threads from the past, and I see that several of you have decided to go with a lower pitch. How has that worked out? I don't see any recommendations for a higher pitch.....
Thoughts, all?

[Joe CD MS 300]

Not an area where I have any experience but I have heard a lot of good things about this outfit. Not exactly around the corner from you though. Are you having specific problems or issues? What is the problem?

[moctrams]

When I replaced Gabbiano's MD7A with the 20hp Beta, I had the folks at Campbell spec it out. They advised a lower pitch. It had something do about the Campbell's prop actually working like a higher pitched prop. I am completely hooked on my new prop. I have great performance and no prop walk in reverse. I can back straight out of my slip.

[Troy Scott]

Joe,

The boat is still apart in my hangar. I'm not actually having any problems other than finding enough time to get her finished and back in the water! I had planned to use the MaxProp I have, but I've decided I don't want to open up the aperture to accommodate the MaxProp. On further examination of the old prop, which I had assumed to be original, I've discovered that it is a substitute, and that at some time in the past it had been a 17-11, and it's been altered to be a 15-14 for my boat. It was also at one time HEAVILY encrusted with barnacles, to the point that the surface of the metal requires sanding to get rid of the evidence. There are little circles etched into the surface. All this has led me to decide that I should probably just buy a new fixed prop.

[Como No Cruising]

Troy: There are propellor reconditioning shops that can likely restore your prop to brand new condition. They usually can modify pitch, polish and align your prop to better than new. You may wish to look into that option. The little barnacle circles you see will come out with sanding and polishing without harm to the prop. We always sand a polish our prop when we haul out for a bottom job.

The Max-Prop would be really nice to have, but I doubt that I would want to go to the trouble and expense to modify the aperature.

Can't wait to see photos of the finished product.

Will

[Boyd]

Hi All:

If you searched the archives then you know I bought a Campbell sailor several years ago. I wont reiterate the trials, just to say they were not a lot of fun. It is a very powerful prop and pitch adjustment is critical. Plan on pulling it at least once and having it repitched. Frank and Jimmy's here in Ft. Laud. did the adjustments for me.

Looking back after living with it more than several years, I find that the improvement in stopping power is its greatest asset. My pervious prop was a two blade and when I went to reverse basically nothing happened except the stern went to port. The Campbell will stop the boat very quickly and that takes a lot of stress out of maneuvering. Prop walk to port still exists and I have come to appreciate and use it effectively. I can turn the boat around in its length plus about 10' seawall to seawall. Backing straight is still a challenge. I can back more or less straight into a slip, assuming no wind or current, if I give it short bursts of power and put the transmission in neutral immediately. If things start to go sideways, I correct by going forward a bit.

I have found no way to prove the claims of lower resistance under sail. Maybe it does and maybe it doesn't. Possibly helicopter effect is going on here.

You have to keep it clean. It seems more susceptible to barnacle buildup than a regular prop. Probably the more sophisticated blade shape is just more sensitive. I scrape with a sharp putty knife and then brush with a SS welding brush every few months. Keeping it clean makes a measurable improvement in motoring speed. If its fouled, the engine will not make its normal WOT rpm's

A minor aside, it will dematerialize a foam crab pot float with relative impunity. The noise is quite startling though.

Since the leading edges are blunt, it picks up sargasso weed relatively quickly. The symptoms are slight drop in rpm's and subtile loss in boat speed. Simply put the trans in reverse and rev it up. That clears the prop and your back on your way.

Would I buy another one. I think I would like to try a conventional 3 blade first and see what happens since I have never had one on my boat. You can get those reconditioned for cheap.

Boyd
s/v Tern
CD30 MkII
Fort Lauderdale, Fla.

[moctrams]

The Campbell prop came already coated with Pettit Prop-Kote. I had no barnacles on the prop when I pulled the boat in October.

[Troy Scott]

Guys,

All very informative! Thanks!
So is the Michigan Wheel sailboat propeller a more "conventional" design (and maybe more predictable as to pitch, etc......)?
I want to get this right. I have found that the collective wisdom of this board is pretty amazing.

Does anybody know what the Pettit prop coating is? I wonder if it's a ceramic like some of the clear-coats found on todays auto wheels.

[moctrams]

Price is $21.00

http://yhst-37334516642247.stores.yahoo ... prkit.html

[moctrams]

Price is $219.00

[Boyd]

They make a conventional 3 blade and a 3 blade "sailor" type. Your choice depends on your relative ratio of motoring vs sailing.

My motoring experience is probably a bit unusual.

I have to travel 45 minutes down the relatively contorted New River waiting for and traversing 4 draw bridges, including one RR bridge which is totally automated, to get to the ocean. With current and wind tunnel effects in downtown Fort Lauderdale, I need all the control I can get. It can get really dicey at times with mega yachts under tow, there is often little space for my small boat to slip through. The Campbell was a huge improvement over a 2 blade. Most of the trip down river is with current from behind. As you know with current behind, there is little or no rudder response. The ability to stop and turn tightly facing upstream is critical otherwise I end up drifting into a bridge.

Is it better than a conventional 3 blade? I cant answer that one. Probably depends on what type of sailing you do. Practical sailor seemed to verify the claim that the Campbell has less resistance when sailing. Like a lot of things, you pays your money and takes your chances.

Boyd
s/v Tern
CD30 MkII
Fort Lauderdale, Fla.

[Jim Davis]

I have had reasonable success with two other Pettit products, for a lot less. These are not perfect, but do a fair job. For $219 a quart that Prop Coat had better be perfect. I can see it if you have a lot of friends, or are a yard painting several boats at the same time.

These spray cans run from ~$15 to 25 each.

1792 Zinc Coat Barnacle Barrier
1793 Transducer Paint

The next time I haul I'm going to simply use a Cold Galvanizing Spray paint from the hardware store, about $7.

No mater what paint you use the prop must be clean and sanded. I use 180 wet followed by an Acetone rinse.

[Ben Thomas]

Though expensive but competitive with the Max, the Variprop is incredible. German engineering at its best. It is made to fit smaller apertures, the hub is smaller, adjustments for forward and (forward)reverse pitch is made externally without dismantling the hub. Pitch is adjusted in very small increments. So fine tuning is enhanced.
I have been using the four bladed Blue water feathering Variprop for 4-5 years now. Beyond pleased, when shifting from forward to reverse or vice versa there is no loud clump but a quiet quiet /firm engagement because of the dampened shock absorber as the blades rotate from forward to (forward pitch) in reverse as they come to the stop.
Impressive thrust
Ben
http://www.varipropusa.com/#vp

[Steve Laume]

I used the Cold Galvanizing Spray paint last August when we finally launched. I will let you know how it works out next spring when I get a chance to dive on the boat.

I used to use Desitin (the babies bum cream) with decent results.

Diving and brushing seems to be the most effective way of keeping the prop clean, Steve.

[bottomscraper]

Using your engine seems to be the most effective way of keeping the prop clean, Rich