Folding prop choice

[Spuddy]

A good pal with a 36'er and I were chatting about folding/feathering props. I said I'd ask on here about different makes and pros and cons. I've seen the other thread but he could really do with suggestions about virtues and features of different models. The main motive is for an extra knot or two.

 

[earlybird]

.. The main motive is for an extra knot or two.

If your pal is expecting that from a folder on a 36 ftr. then I suggest he saves his money and avoids disappointment.
Otherwise, suggest a Flexofold 2-blader, which might give 5% to 10% speed increase under the most favourable conditions.

 

[cliffdale]

After going down the same road my self, I have just ordered a flexofols 3 blade. The advantage of 3 blades will give you more bite in a sea way.

Did you read the review on folding props?

Cliff

 

[Tranona]

Is it extra speed under sail or power?

All feathering and folding props have lower drag than fixed props so should lead to improvements in performance under sail, particularly in light airs. However 1 to 2 knots is unrealistic - that is somewhere between 20 and 40% over typical cruising speed under sail for a 36 footer! On the other hand performance under motor varies from design to design and in comparison to the current fixed prop depending on type.

Your mate needs to be more specific about what it is about the current performance of his boat he wants to improve, and his expected pattern of usage. Clearly also important to know what sort of engine/drive/prop is currently fitted.

 

[cliffdale]

Here is the link I was looking for. http://www.youtube.com/watch?v=B4xwJkUfU6o&feature

Little bit here
http://www.ybw.com/forums/showthread.php?t=302042

 

[snooks]

A good pal with a 36'er and I were chatting about folding/feathering props. I said I'd ask on here about different makes and pros and cons. I've seen the other thread but he could really do with suggestions about virtues and features of different models. The main motive is for an extra knot or two.

Here's a PDF of the Yachting Monthly folding prop test from the nice people at Flexofold

 

[haydude]

Hi snooks,

Are there any plans for YM to do a similar test for saildrives? The test published on YM helps a bit but does not quite apply to saildrives and does not include possibly the most installed standard propeller for saildrives which is the Volvo Penta. All those tested are "aftermarket", which means they are not usually coming as standard on new boats.

 

[pelissima]

Here's a PDF of the Yachting Monthly folding prop test from the nice people at Flexofold[/QUOTE]

The Kiwi one prooved the easier to install.
You can make a carefull entry in this area as I give away mine half price plus freight.
(RH, 30mm shaft, used on a First 38)

 

[Spuddy]

Thanks, chaps. It was improved sailing performance he was after.
The links are much appreciated - I'll have a look and pass them on.

 

[sjdtuk]

I find that a 2blade Flex-O-Fold drives my Nic 45 just fine.

 

[snooks]

Hi snooks,

Are there any plans for YM to do a similar test for saildrives? The test published on YM helps a bit but does not quite apply to saildrives and does not include possibly the most installed standard propeller for saildrives which is the Volvo Penta. All those tested are "aftermarket", which means they are not usually coming as standard on new boats.

We did try to get a Volvo and Radice to test, but they didn't make it in for the deadline.

The test was primarily for the aftermarket consumer, although there are many mfgrs who will supply the prop you want.

How much we would gain out of doing it on a sail drive I'm unsure. It took three days to do the last test two full days of booking out Lymington Yacht Haven's hoist and 14 lifts. While it is possible, unless some new props come around I don't see YM repeating the test any time soon. But we're getting a new editor at the end of the months so who knows what they have planned

 

[samwise]

Our three blade Featherstream gave us about an extra knot in sailing mode which, as we all know can make the difference between making the pub before last orders and not. Top speed under power is not enhanced by much, but the extra bite from the three blader provides excellent astern and stopping performance.

 

[savageseadog]

I feel the main advantage of three blade props is the reduced diameter for the same push. Nothing wrong with two bladers in my opinion although I use a Kiwiprop these days.

 

[Tranona]

Hi snooks,

Are there any plans for YM to do a similar test for saildrives? The test published on YM helps a bit but does not quite apply to saildrives and does not include possibly the most installed standard propeller for saildrives which is the Volvo Penta. All those tested are "aftermarket", which means they are not usually coming as standard on new boats.

Just about all of the props in the test are available for saildrives (Featherstream is an exception). The results will be very similar to shaft drive. Obviously the Volvo props are more poular on Volvo saidrives, but if you look around you will find many other types fitted. The FlexoFold on my saildrive performs well and hopefully will be more durable than either the standard fixed prop of the Volvo folder.

 

[BAtoo]

Had a Gori 2-blade on the previous boat; got a Radice 2-blade on this one - both folders not feathering. Would expect 10% increase at most. Had no problems with either prop - both going forward or reverse.

 

[Slowtack]

My 3 blade Volvo folder works well,simple and robust. Great for stopping too!

 

[haydude]

My 3 blade Volvo folder works well,simple and robust. Great for stopping too!

Mine too if only it didn't make the boat shake like in an hearth quake.

I had a new VP folding 3 blades installed last November. Immediately I noticed a significant vibration. Out on a sea trial with the local Volvo Penta dealer and he confirmed the issue. He had to make a claim with Volvo who agreed to replace the propeller and pay for lift and relaunch.

The second week of January the dealer received the new propeller. He checks the hub, the hub is not turning true on its axis! So he makes another claim and sends it back. Second new hub arrives, he checks this one too: the hub is off centre to its axis. New claim and sends it back. Clearly there is a serious production issue with VP folding props. I still have the first one, and fortunately we are still in the season when I do not do long passages.

Faithfully awaiting replacement.
I have to praise my local VP dealer because:

1) he did listen and acknowledged the issue
2) he is taking the matter seriously and he is checking the quality of the replacements he is being provided.

 

[blenkinsop]

We have been pleased with the performance of our 3-blade Varifold on our Starlight 39, although since it replaced another folding prop we cannot compare performance with fixed blades.
Also good service from Bruntons and First Marine Propulsion of Shamrock Quay who supplied replacement blades at minimal cost when we found we had given them the wrong specs!

 

[Bosun Higgs]

The Radice is cheap but its an old heavy design. It works but if it ever dropped off my prop shaft I wouldnt replace it with another Radice.

 

[bignick]

Mine too if only it didn't make the boat shake like in an hearth quake.

I had a new VP folding 3 blades installed last November. Immediately I noticed a significant vibration. Out on a sea trial with the local Volvo Penta dealer and he confirmed the issue. He had to make a claim with Volvo who agreed to replace the propeller and pay for lift and relaunch.

The second week of January the dealer received the new propeller. He checks the hub, the hub is not turning true on its axis! So he makes another claim and sends it back. Second new hub arrives, he checks this one too: the hub is off centre to its axis. New claim and sends it back. Clearly there is a serious production issue with VP folding props. I still have the first one, and fortunately we are still in the season when I do not do long passages.

Faithfully awaiting replacement.
I have to praise my local VP dealer because:

1) he did listen and acknowledged the issue
2) he is taking the matter seriously and he is checking the quality of the replacements he is being provided.

You have checked that your taper is centred, or if you're on a saildrive that the splines are centred haven't you? Seems that it would be massive odds that all the ones you've tried were all out of alignment..... If the taper is off centre, or the bearings have gone in your saildrive, then whatever you fasten to them will oscillate,,,,, Not wishing to doubt you but just hope you've checked everything before sending so many back.