Folding vs feathering vs standard?

[GTom]

I am curious what are the advantages/drawbacks of a folding prop vs a feathering one?

Obviously a feathering prop has a little more resistance, but this doesn't seem significant:



Is a folding prop more prone to failure than a feathering one?

[gjordan]

Practical Sailor just arrived in the mail yesterday and it has a very good article on folding Vs feathering. The graff is hard to figure out, but there is a lot of information. Grant.

[s/v Moondancer]

I have met a few cruising sailors in boat yards with folding props that have failed. A friend with $750,000 cat just threw his folding props away and fitted fixed props because of recurrent failures.

I am presently 1,700 nm from the nearest haulout facility...not a place for a folding prop to fail.

[SV Bacchus]

I've not had a folding prop so I can't speak to them. I DO have a Max Prop, which is a feathering prop. The boat was delivered new with them installed, a 2004 Leopard 42 with 40HP Yanmars.

Forward seems "normal" and sailing with them feathered is quite good but reverse is where they seem to shine. I feel I get the same performance in reverse as in forward. They have gotten me out of a sticky situation or two, you know, wind, current and nasty pilings..

[boom23]

Never had a problem with FlexoFold. They are almost maintenance free.

[hellosailor]

Feathering, as in variable pitch? Can mean more moving parts, more expense, as opposed to the simplicity of a folding prop.

[robert sailor]

All i have ever sailed with for close to 40 years have been feathering and folding prop, I've never had a failure. My personal preference is 3 blade folders. If money is tight, go with a fixed.

[kenbo]

Folding prop:

- a bit more streamlined, less drag
- blades have a "normal" curve to the blades so more efficient in forward
- less efficient in reverse
- pitch is fixed so fitting can be trial and error
- less likely to snag a line (lobster pot, fishing buoy)
- tend to be a bit cheaper

Feathering prop:

- Blades are flat so a bit less hydrodymanically efficient
- can generate same thrust if forward and reverse
- pitch is user adjustable, sometimes in the water

I'm sure others can add to this list

[Jammer]

Originally Posted by GTom

I am curious what are the advantages/drawbacks of a folding prop vs a feathering one?

Either a folding or feathering prop will improve performance under sail compared to a fixed prop.

A folding prop will cost you performance under engine power when in reverse, and will not work on some boats that have a propeller aperture, because when folded it will hit the rudder or skeg.

The very best feathering props have few drawbacks other than cost. Cheaper ones give up some performance under engine power in both forward and reverse.

Any of them can jam.

[JPA Cate]

Our first Insatiable came with a 3 blade fixed prop, which was changed for a 2 blade folder. That was good for an increase of 1-1/4 kn boat speed in light airs. We cruised locally on weekends, and had a few trips to Southern Calif. during the ensuing time.

Six years later, in March of 89, we left the US for the second time out. The first year, 2 yrs, previously, we had cruised from San Francisco, to Mexico, the Marquesas, Tuamotus, Societies, and return via HI. Then, in about 1990 or '91, having arrived in NA, we had to re-bush the two blade folder.

Sometime later, we fitted that boat with a feathering prop. The featherer gave more power in reverse than the 2 blade folder, but also way less fuel efficiency motoring--a 25% cut, iirc.

When we got this boat, it had a 2 blade Gori prop, which failed due to a re-bushing attempt with the wrong metal. So we bought our current Flex-O-Fold 3 blade folder for it. We have been pleased with the reliability of the FOF--we have a little over 59,000 miles on this boat, now.

Ann

[senormechanico]

Jammer,
You might want to modify your second paragraph.
It looks like you meant a folder, not fixed.

Over 30 years and two sailboats, I've had both a MaxProp and a couple of folders.
The MaxProp 3 blade was as Kenbo described.
The first 2 blade folder was on my Dragonfly when I purchased it.
I eventually replaced it with a 2 blade Varifold.
It is more efficient, but in hindsight, I should have gone with a 3 blade to cut down on vibration. It's at its worst at cruising rpm.
I don't really fault the prop, but the relatively flat bottom of the boat right above it as there's a hull resonance at cruising speed's sweet spot.
Other DF1000's have mentioned the same problem.

[Jammer]

Originally Posted by senormechanico

Jammer,
You might want to modify your second paragraph.
It looks like you meant a folder, not fixed.

You're right. I've missed the edit window though so I can't change it.

One of the facts to consider, as you point out, is that the benefit while sailing is in light to moderate conditions. In strong winds the prop makes no difference. I don't have personal experience but it is my understanding that in very light airs the prop also makes little difference.

[robert sailor]

Originally Posted by Jammer

You're right. I've missed the edit window though so I can't change it.

One of the facts to consider, as you point out, is that the benefit while sailing is in light to moderate conditions. In strong winds the prop makes no difference. I don't have personal experience but it is my understanding that in very light airs the prop also makes little difference.

There are those that share that opinion, while I won't debate whether your biggest effects are above light air I believe you have a clear advantage over a typical large fixed prop in light air as well..

[kenbo]

Originally Posted by robert sailor

There are those that share that opinion, while I won't debate whether your biggest effects are above light air I believe you have a clear advantage over a typical large fixed prop in light air as well..

There are a few benefits beyond increased speed in light to moderate wind. If the prop is forward of the rudder, less turbulence can be felt and the rudder will see less disturbed water.

Also tacking in light wind is easier without the additional drag of the fixed prop. Modest improvement but it is noticeable.

[Gary Mc]

Being one of those silly racers I have always had a folding prop, I always buy a Gori.
They are a geared prop so both blades will always fold, and the prop blade seems to have much better shape than the well known non geared competitor. Performance in forward and especially reverse it hugely different.

I have had no issues with them except that with extended use they do wear and eventually have to be reconditioned or replaced.