If you had an offset propellor, would you prefer folding or feathering?

[DoubleEnder]

This would be on a small long keeled sailing yacht. Current install is a 12 inch 3 bladed fixed prop offset to port. Not sure of the pitch, yet. Engine is 10hp. If I were to upgrade, (to reduce drag when sailing which must be significant) what do you think? Folding, feathering, pros &cons from experience?
thank you

 

[Tranona]

Small folding propellers are very limited in choice with not much under 13". Best bet would be a Featherstream 3 blade. I have had both folders (Flexofold) and featherers (JF and Featherstream) the JF is the forerunner of the Featherstream and it was fitted to a Yanmar 1GM and then a Nanni 14 although that was atypical as it had a 3:1 reduction and 15". If you have a 1GM then suspect you have the 2:2:1 with a 12" propeller. a Featherstream 12" as the big advantage of the option of a different ratio in reverse which is really useful for the Yanmar box which has a 3:1 reverse. So expect much better reverse performance because you can match the pitch better. Cornish Shrimpers fit that propeller in the 19 and 21 with a 1GM.

In general you will notice a difference in sailing performance, particularly in light airs, at least equal motoring in forward and better in reverse. A 2 blade folder may not give as good motoring because at 12" there is less blade area, but a 13" would be better, although you may then get tip clearance issues.

Suggest you talk to Darglow Engineering.

 

[wonkywinch]

Second a recommendation to speak to (Nick at) Darglow. They make the Featherstream and are UK agents for the Flexofold. Their workshop in Wareham is like an Alladin's Cave of polished bronze!

 

[Daydream believer]

A feathering prop is more inclined to collect weed etc when not in use. My Brunton is a pain for that & would be a problem without the rope cutter. I would not have another feathering prop.

 

[B27]

Folding props are often available secondhand at sensible prices.
If the 12" is right for 3 blade, then 2 blade folder may need to be bigger? Will there be space?

It's definitely worth doing from a drag point of view when sailing.

 

[DoubleEnder]

Many thanks for this. Helpful as ever

 

[Romeo]

How small is the yacht? To properly reduce drag you could change to an electric outboard hung over the side.

 

[B27]

How small is the yacht? To properly reduce drag you could change to an electric outboard hung over the side.

Outboard 'over he side' is not exclusive to electric.

 

[bedouin]

I have an offset prop with a moderate keel. When I bought the boat it had a 2 blade fixed and the behaviour of the boat with the engine in reverse was extremely unpredictable.

I replaced that with a 3 bladed folding Gori and that transformed the boat handling under power.

The choice of the Gori over other alternatives was due to physical constraints. In other installations I think the Darglow or Autoprop (or Kiwi or Maxprop) would be (almost) as good. Note the 3 Blade Gori is an unusual prop and probably works better than a 3 bladed fixed prop.

The issue may be with how large a prop you can fit. I could only fit a 15" and it was only the Gori 3 blade would fit.