Folding/feathering propeller

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robertj

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I’m taking the plunge on fitting a feathering prop to my 35’ boat of around 6.4t loaded.
It’s certainly a buyer mine field knowing what to go for.

I need people’s experience with their folders and feathering props, with an honest opinion of their pro’s and con’s

Thanks
 
I went to the Southampton Boat Show last year and spoke to all the folding prop suppliers. Ended up with a Brunton's two blade varifold that was fitted last month. The only difference I've noticed is a) more noise under engine from the prop, but silent when sailing (one of the reasons for getting it) and b) a slight amount of prop kick when before we had none.

10.1 meter fin keeled boat about 5 tonne fully loaded.
 
We have owned a Bruntons two blade Autoprop for 20 years. Never had any problems with it and it performs perfectly. The gearbox needs to be locked when sailing as the prop will rotate when water flows across it.
 
Boat fitted with a Volvo 3 blade folding when new to us in 2006. Works just fine. When sailing, a brief selection of reverse closes the prop and the shaft stops rotating.
 
I've had 2 blade Flexofold on a 25 footer (bought from Darglow) and a 2 blade folding Gori on a 27 footer.

Both worked perfectly in forward and reverse and gave no more paddlewheel effect than the fixed propellers they replaced. Darglow were a huge help when measuring the propshaft of my boat as it turned out my boat's taper was non-standard so they machined the hub as part of the deal.

If I were buying again my first choice would be a Flexofold and I'd happily go back to Darglow for it.
 
Our last boat 33' around 5 tons D1 30 hp and saildrive came with a Volvo three blade folder, before then we had always had two blade folders, I have never owned a boat with a fixed prop. The boat could make serious headway against wind and tide, the engine ran at 2k revs to give 6 kts. burning 2l. per hour. Pushing her up to over 7 kts was easy but doubled the fuel consumption. Only downside was the tiny anodes which struggled to last a full year.
Our current boat Moody S 31 much shorter waterline but not a lot lighter came with a 19hp VP saildrive with VP 2 blade folder, she really stuggled against a strong wind and sea, speed dropping to 4 to 4.5 kts. After a lot of research and agonising I spent close to £2k on a 3 blade Flexofold from Darglow, the VP 3 blade could have been about 20% cheaper but the Flexofold has a much bigger hub anode. I had hoped to get 2 years out of it but not so far though this year I have painted the prop. to see if that makes a difference. The motoring performance is greatly improved, she manages 6kts at 2,250 revs using 1.3 l. per hour and in adverse conditions is about a knot faster. About a knot slower than the Finngulf but that is a much faster hull shape. As we get older we are motoring a lot more, rarely beating unless the sun is out and the tide is under us. Reversing is instant and powerful enough to extract me all the way out from Oban Marina a week ago in reverse against a 35 kt. NW. ( Couldn't get her turned in that wind in the space available between the pontoons)
So I am convinced about three blade folders, as for the choice between VP and Flexofold I think the performance is similar, the VP blades look more elegant, the Flexofold has disappointed me so far regarding anode life but perhaps with the prop painted I may be able to stetch it to 2 years which would mean I could reduce lift outs by 50%.
 
We fitted a Darglo Featherstream about four years ago. The boat is a 39ft 6.6ton 1990s cruiser-racer with a fin keel, 40hp engine, saildrive and balanced spade rudder. The main reasons for doing it were noise and vibration from the old fixed three blade prop and the desire to fit a rope cutter. Darglow were extremely helpful in specifying the right prop for the job and offer one free pitch adjustment if it isn't quite right. Ours was right first time - we can just get maximum power in ahead by which time the boat is doing 7.7 knots! And the acceleration in astern is astonishing. The large anode on the prop hasn't needed replacing yet but we get through one saildrive anode per season. As stated above you need to put the gearbox in astern after stopping the engine to feather the prop then you can return it to neutral.
 
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Just to add
Price - Flexofold will sell directly undercutting Darglow list price, but Darglow offer a winter discount which makes them competitive. A google search will find a supplier in SW England (FalmouthYacht Brokers?) who offers a discount on the Volvo Penta. Darglows knowledge and expert advice adds value.
Comparison from 2 years ago, Flexofold 2 blade 17" Darglow £1080, Denmark £1150, 3 blade 16" Darglow £1902, Varifold 3 blade Autoprop £1675 (with MOA discount) VP 3 blade Falmouth £1526. VP price the hub and blades separately, the VP would have been the best value offset by the shorter anode life and Darglows expertise in sizing. (With Brexit approaching all these prices will have risen quite a bit?)
Durability- The VP was used for 9 years perhaps 2000 hours without appreciable wear, so verygood, the Flexofold has only done 2 so can not report yet. the Flexy was offered with an optional composite hub at a higher price, I thought perhaps someone else should test it first.
Anodes - The Flexofold is available with zinc or alumininium, much bigger cone shape.(which I use for a combination of fresh and salt water) I could only find zinc anodes for the VP.
 
+1 for Flex o fold 3 blade. Get Darglow to spec dia and pitch. I now sail much larger % of time , it avoids prop rotation and is compatible with sail drive (not all are). Darglow will also do mod to suit Stripper.
 
Darglow Featherstream works perfectly for me, along with superb after service and advice. If I'd ever buy a new boat, I'd buy another prop from them.
 
We have a Volvo Folding prop.
I have a fear of lobster pots and feel that a folded prop is less likely to get caught than a feathering one. Obviously if motoring it would make little difference but when sailing...
I might be wrong though!
 
I suspect its really hard to say as most might have limited experience of varying makes on same boat.
We had a volvo folder on our last boat with volvo sail drive and was fine .

We now have a J prop which equally fine but whether its better than if we had fitted another volvo cannot say. My only comment is that if looking at a new prop just make sure any rope cutter you have currently can be adapted to fit the prop of choice (most have kits but do they all?) or if you dont have a rope cutter obtain one eg ambassador etc at same time. I suppose you might also want to see how easy it is to replace any prop anodes when time comes?

I guess it comes down to budget
 
PBO did a group test a few years ago, I'm sure I've seen an online copy of it somewhere.
What they found matches with my limited experience- I have a Varifold and they found it to be the slipperiest under sail, adequate motoring ahead, and poor thrust in astern. FWIW I'm fine with that, and it had no anode and zero maintenance requirements.
 
jamie N said:
Darglow Featherstream works perfectly for me, along with superb after service and advice. If I'd ever buy a new boat, I'd buy another prop from them.
Click to expand...

+1

Some other considerations:
What sort of keel, prop & rudder arrangement do you have? ie: is the prop in a cut out or similar? will the new prop fit, including in reverse?
Do you have or are you planning to fit a rope cutter? might a new prop foul it?
 
I've fitted a 3-blade Flex-o-Fold to my 41ft AWB with Yanmar SD50 saildrive. Bought from Darglow during winter discount period. Also fitted the Ambassador Stripper.

I have a very high opinion of this product. Power/response ahead and astern is very good, no discernible kick.

My saildrive manual says that prop must be allowed to spin. The noise from a fixed prop was intrusive and annoying.

I remove it at haul-out, dunk it in brick cleaner for half and hour and refit it at the start of the season. It's a very well made product.
 
I have a brunton auto prop. Not entirely happy with it, although it is excellent for motor sailing. One problem with a feathering prop is that i sail round the channel islands and N Brittainy a lot. That area seems to get a lot of weed that has long stringy stems. When sailing the prop can catch this, in the same way a fixed one would.This will happen even without prop rotation and can be a pig to get rid of. Same with pots and bits of net etc. A folder would probably not have the same issue as the weed might slide off. I do not know, but worth considering.I have a rope cutter and consider it an essential addition to the prop
 
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On my Fulmar I have a 2 bladed folding Gori propeller on a shaft with P-bracket. It works brilliantly ahead and astern. Usually need to select reverse to close the blades and stop t spinning, then into neutral. This is unnecessary if sailing over 4 knots. Sillette.co.uk are excellent with advice and machine the taper in the price.

I first experienced folding propellers in the early 1970's and everyone has been a Gori. Never had a problem with any of them.
 
Kelpie said:
PBO did a group test a few years ago, I'm sure I've seen an online copy of it somewhere.
What they found matches with my limited experience- I have a Varifold and they found it to be the slipperiest under sail, adequate motoring ahead, and poor thrust in astern. FWIW I'm fine with that, and it had no anode and zero maintenance requirements.
Click to expand...

Just Google the thread title adding the word test to find the YBW report.
 
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