Feathering props - any good?

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Fourbees

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Our new (to us) boat has a folding prop, which we hate, in particular as it is very poor in astern (needs full revs to stop 8-ton boat approaching a lock gate v. slowly...). Also in ahead, it engages with a loud bang (very annoying). SWMBO fancies fitting a feathering prop at our winter lift-out, but it strikes me that anything that needs to feather is more likely to go wrong than a fixed prop, which is also cheaper. We don't race so are not looking for the extra half knot. Anyone got experience of feathering props, good or bad, or advice on this question?
 
Had a Brunton Autoprop for something like 12 years now, 2200 hours on the engine installed at nearly the same time. Superb, does everything it says on the tin. Never had any type of problem with it, 15 minutes maintenance once per season. Reduces prop walk, increases power into the water. Only down side is that they are rather expensive.
 
I fitted a Maxprop 12 years ago. It still works well. Today I would go to a Brunton's Autoprop. (I had not heared of it at the time).
 
I fitted a Darglow JF feathering prop to my 31 footer in 2002, to overcome a marked prop walk effect in reverse. It cured that problem completely and the bit of added speed and reduction of turbulence felt on the rudder was a bonus.
I've just returned this prop to Darglow at Southampton boat show as it has become "floppy" and inefficient and they say they can overhaul or trade in for a new Featherstream. [JF no longer available]. The knowledgeable lady said that 12 to 15 years is about what you can expect before a major overhaul. I expect a quote of £200 / £300 for overhaul. or £1000 for trade up.
I've temporarily put the old fixed prop back on, but don't want that permanently.
 
Fourbees said:
Our new (to us) boat has a folding prop, which we hate, in particular as it is very poor in astern (needs full revs to stop 8-ton boat approaching a lock gate v. slowly...). Also in ahead, it engages with a loud bang (very annoying). SWMBO fancies fitting a feathering prop at our winter lift-out, but it strikes me that anything that needs to feather is more likely to go wrong than a fixed prop, which is also cheaper. We don't race so are not looking for the extra half knot. Anyone got experience of feathering props, good or bad, or advice on this question?
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All folding props are not equal. Sounds like you have an especially bad one, quite possibly quite an old one...?

The folder on the Elan is fine, though it is sometime reluctant to open in reverse when the boat is moving forwards at speed. But I know about this so plan my berthing appropriately.

The folder on my Dad's Dufour though has none of these issues, and as it's a 3 blade one it has some incredible grip. After it was fitted I carefully backed the boat out of the berth, spun the wheel and applied lots of revs as I'd been used to with the fixed 2 blade it came with. The boat accelerated so fast I fell over!

To overcome the poor in astern thing you could try gradual increase in revs, rather than just going straight through the box as many do. That seems to give better results.
 
Done 3000hrs on a 20" 4 bladed Variprop (German made) with no problems. Just greased it each winter at lift out. I especially like the "brakes". On the charter market it enabled inexperienced skippers to stop quickly if they cocked up a berthing in addition to having max astern power of any prop to pull you off the putty.

Featherstream has a max shaft size of 30mm which they will bore out a bit more so it sits further down a 35mm taper.

Maxiprop need a larger hub for "heavy" charter use. Pitch is set on hub during build.

Kiwi probs is only good for small low power boats and various people have problems with "fixed" astern pitch which seems to coarse.

Flat blades of a feathering prop means that manufacturer will quote slight oversized dia x pitch to give same power of a fixed/folding prop with shaped blades.

Now boat not on charter changed to folding prop after hearing from a number that astern power on latest ones is improved. My impression is slightly better sailing performance and motoring performance but you can still make a cup of tea while engaging astern!

Now little confidence in stopping power and entering berths much slower which caused difficulty in strong crosswinds.

I am beginning to understand it and think it better to engage astern with a bit of power then blip the throttle for more stopping power.

I suspect that astern power on folding may be improved but its still far less than the best - which is feathering.

Seriously thinking of going back to feathering.

I would only buy a Variprop as pitch can easily be adjusted/tuned from outside prop. I always go for overproped and that restricts max engine revs. Trial & error to get best optimum results for your hull shape/length/engine power.

I get a bit fed up with the many on here that talk BS regarding props possibly as their new "super" prop (insert any make) is a better match for the boat that the previous fixed prop.

Like boats ALL props have some degree of compromise eg Brunton autoprops are best for motor sailing but have more water resistance than folding (least) or feathering (next least).

Variprop as a make suffer IMHO in having Bruntons as their distributor as (again IMHO) Bruntons always push their autoprop in preference.

Best for forward power is a fixed or folding prop.

Compromise is therefore how important is least sailing resistance v motoring economy/power v motor sailing power v brakes and astern power.

FWIW my current thoughts are feathering is best for me but will give the folding a yrs trial. Boat is 43' and 75HP.

Hope this helps.
 
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Sailfree has summed it up nicely. A good folding prop does not behave in the way yours does. It is probably worn - either the pins or the gears, or both. Blade designs have improved from older ones which were intended to replace skinny fixed props on racing boats. I have a Flexofold 2 blade which performs exactly like the fixed one it replaced, but as Sailfree says you need to get some revs on to open it promptly in reverse. This effect is perhaps worse on my boat because it is a saildrive so the prop is nearer the centre of the boat.

I also have experience of a feathering JF, similar to the later Featherstream. Would have chosen one of these in preference to a folder if it had been available for a saildrive - it is now.
 
I've never had a boat with a fixed prop. First two were 2 blade folders and never gave me any problems. I now have a Featherstream and have just settled the invoice for gelcoat work to the bow after it failed , without any warning, to provide astern power entering a berth. To be fair, it had gone 18 months without a regrease but if I was buying now I would definitely go for a folder.
 
Sailfree said:
I get a bit fed up with the many on here that talk BS regarding props possibly as their new "super" prop (insert any make) is a better match for the boat that the previous fixed prop.
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Since fitting the Autoprop my boat is more economical on fuel, faster at lower revs and faster sailing compared with the fixed prop originally fitted by the builder.
 
I've had a Kiwi prop for the past year and am very happy with it. I cant compare it directly with the old fixed three blade as I changed the prop,shaft and engine together.
I cannot comment on the sailing difference either as I also got a new set of sails at the same time.

Obviously the boat feels much nicer to sail...
 
Autoprops seem to work well for some but can be problematic for others - much depends on the underwater hull configuration. We had an Autoprop for three years which caused numerous problems. We changed to a 4 blade Variprop, for which I have nothing but praise. Very well engineered and performs well.
 
I have a MaxProp looked after by Chris at darglow and they are both excellent! My boat sails well, motors well, cured the excessive prop walk and the ability to set the pitch means I can get the revs I want.
 
Puggy said:
I have a MaxProp looked after by Chris at darglow and they are both excellent! My boat sails well, motors well, cured the excessive prop walk and the ability to set the pitch means I can get the revs I want.
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+1 for max prop. Loads more umph than my old fixed 3 blader. Primarily because I went from 17 to 19", however much less drag for sailing, and I've overpitched slightly so cruise at about 500rpm less than before.
 
Thanks all of you. I think perhaps we might go for an Autoprop and see how we go. In the meantime, we'll have to put up with the dodgy folder for the rest of the season - hope to get a few more weekends in!
 
What you can choose may depend on shaft size. Some feathering props including the Autoprop are heavy and have a longer overhang than others. When I bought a new prop I needed to increase the diameter from 20 inches to 21 inches because the old one was sized to the 30mm shaft rather than the 88 horsepower engine. Bruntons told me that their propeller would be too heavy for the shaft. I settled on the Maxprop and am very pleased with it. If you use a 20 inch or smaller prop the Featherstream appears to be a very good option with quite a cost saving over others. Darglow were very helpful when I bought my Maxprop, and it gives me more speed at the same revs and better sailing in light winds than the old fixed three blade prop.
 
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