Upgrade prop to a feathering prop

[patrscoe]

We have just put our sailboat on the hard for the winter with the intent to do several projects. One is to upgrade our fixed prop with a feathering prop or a folding prop.
I really like the feathering props but would like to have some additional input from users.
Based on previous users, are there any disadvantages with feathering props?
I believe the advantanges would be the grip in reverse and decreased drag while sailing as I hear it may gain upto 15%-20% or about a knot.
I am unsure if you would improve your forward speed under power.

Are feathering props better or worse then folding props?

Any recommendations on manufacturers? I.E. Max or Kiwi


Thanks

[Arpegecap]

Folding props give better performance when sailing. Feathering props are better for powering, especially in reverse with a Maxprop. At least this has been my experience.

Regards,

Bob

[LakeSuperiorGeezer]

I just took a quick look at Propeller Handbook by Dave Gerr and Bob is correct. Another option is the controllable pitch propeller used on larger heavy displacement sailboats where the choice is to use the engine quite a bit of the time. A controllable pitch gives significant increase in economy for tugs, trawlers and motorsailers because of varying conditions of load. Fully feathering controllable pitch propellers have no more drag than fully feathering propellers and the ability to adjust pitch while motoring allows for maximum thrust with any selected engine RPM. This results in increased economy. By the way, a folding or feathering propeller will have efficiency reduced to 90 to 95 percent of the full amount because the shape of the blade is optimized for minimum drag when not in use. Also though, a poorly designed propeller installation can have higher loss of efficiency that this. If you already have a two blade propeller that can be positioned behind the deadwood when not in use, you may want to just keep things as they are.

[tommays]

On the flex-o-fold sight there is a PDF of the test done by a British sailing magazine of pretty much every prop on the market

I am going with the flex-o-fold as i like the self cleaning nature of the gears on there blades as on one of the boats i sail on the prop has no gears and a lot of caution is required to ensure it is open correctly

[jimrafford]

We had a folding prop on our previous cs. It was great sailing but motoring into any sea or towing a dink, it was terrible. Switched to a max prop. Equally good sailing and much better thrust motoring. The max prop had excellent stopping power but a lot of prop walk.
Our current cs came w/ a fixed 2 blade. I looked at all the options on the market that would allow me to adjust pitch in the water and settled on KIWI mainly because of cost. We've been pleased w/ performance sailing and motoring. The Kiwi has excellent reverse and supprisingly no prop walk.
Jim

[SkywalkerII]

I've used fixed, feathering and folding props. I really like the feathering prop for control in reverse when docking. Under sail, they are great. I've used Variprop and Maxprop and never had a problem.

I have a Maxprop sitting on a shelf that doesn't fit my Tartan 27, if you are interested. It was totally reconditioned by Maxprop.

Skywalker
T27 249

[fallard]

I've had a Maxprop for 15 years. Pros: feathering, reverse thrust equal to forward thrust, ultra reliable, outstanding customer support. Cons: expensive, relatively thin blades need to be protected from hard objects and galvanic corrosion, lack of blade cupping means lower efficiency.

Bottom line: would recommend a feathering prop in general and the Maxprop in particular if you can afford it and aren't towing a dinghy on a regular basis.

[Faster]

Very happy with our Max prop... slick piece of engineering, that.
The Kiwi prop is much less expensive than the Max (Kiwi has a reputation for overpitching in reverse. This can be fixed by adding some limiting screws,) but it's definitely a notch or two below the Max. Folders by Gori and others are similar so do some pricing and research and decide accordingly.

Folders are fine if they are 'geared' to ensure that both blades always open together.. a half open non-geared folder can feel like your boat's coming apart at the seams. Our martec had worn and splayed the cheeks as well, so it was a source of vibration.

There are lower-profile fixed props too like the Campbell Sailer prop, we had a good experience with a 3 blade version but others have not had so much luck.. quite a cost savings, though over the others.

If it's in the budget I'd go for the Max or a similarly engineered one... then Kiwi, then a geared folder, esp if you're racing. But IMO the greatly improved reverse thrust of the Max is really worth something.

Originally Posted by fallard

.....and the Maxprop in particular if you can afford it and aren't towing a dinghy on a regular basis.

Could you expand on this?

[JimsCAL]

My last two boats have had Martec Eliptec folders.

eliptec-info.gif

They are simple and fool-proof, and the least expensive option. Martec is a great company to deal with and the really back up their product. A reconditioning is recommended every 5 years or so to keep them working properly. Do that and you won't have the problem of the blades not opening correctly mentioned above.

[fallard]

To Faster's question about towing a dinghy: If you regularly tow a dinghy, the reduced drag of a feathering/folding prop while sailing will be minimal compared to the drag of the dinghy. You might find it hard to justify the cost of something like a $2K Maxprop in this case.