Feathering props

[Abigail]

Hi folks - wisdom please.

Our 40' 14 ton Maxi 120 has a feathering prop fitted by the p.o. We are a bit concerned that it's not worth the vaunted gains in speed. Sometimes at over 1800 revs it starts to squeak, in a cutless bearing type way. We have hauled out and had a good look and nothing appears to be wrong inside or outside the boat.

Possibly one blade has very slight more play than the other two, but we (crew and engineers!) think this may be the product of overstimulated worry rather than reality.

Everyone we talk to says these things are not worth the bother, and we have heard some scare stories. We find the extra welly needed to flick the blades out and give power can also be a major pain in confined quarters.

So - we are pondering whether to replace this prop with a straightforward one at the next lift out.

What are the collective words of wisdom? Thanks in advance.

<hr width=100% size=1>Sarah & Pip

www.greatlittleboats.com
UK & Ireland distributors of Swifgig

 

[dralex]

We have a folding prop on our boat- it gains about 0.5-0.6kn when folded. As long asyou know it's there and know to give things a few more revs when needed, I don't find it a problem.

<hr width=100% size=1>Life's too short- do it now./forums/images/icons/wink.gif

 

[Sunnyseeker]

My experience with a folding prop put me off the idea unless your on a pure racing yacht.
We caught some net off the Spanish coast, after much forward /reverseing it cleared, it was dark and rough so didn't fancy the swim idea..
Arrived very tired in strange harbour, tricky parking due to strong wind so had some speed on, went for the quick blast astern....Nothing... avoided most hard bits of the marina, and parked. Mornings inspection revealed blades still had some net in the folding gears so they had folded as I went to go astern and then not come out again!
Later the same year went astern followed by loud crashing noise from engine, and no reverse...the prop had thrown one blade off, resulting in lots of vibration and the engine jumped off its mount....we changed to a fixed at this point. which has loads of ooomph in both directions!

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[Witchdoctor]

I hate to get techie or nerdy, but are you talking about a feathering or folding prop? Your discription of the blades flicking out implies you have a folding prop which I am told do have a limited life. ie the gears can become worn and the blades can stick. If however the blades swivel or rotate about an axis so the blades are streamlined when sailing you have a feathering prop. These too can wear but bearings etc can be replaced. You really need to find out what type you have and from which manufacturer. Maybe an old invoice with the ships papers will give you the answer.

I have a Bruntons Auto Prop which technically is a feathering prop but is pretty unique in the way it works. I have no doubt it is much better than the fixed three blader it replaced. I changed my prop as I have got nearly a knot of extra speed on all points of sail and more efficient motoring to boot. The whole propeller topic is huge and you will doubtless get as many different opinions as anwers.

Julian

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[snowleopard]

the maxprop is claimed to give equal performance ahead and astern. it can also be re-pitched by the user. on high performance boats it is possible for the prop to un-feather itself and bump start the engine at high sailing speeds.

the brunton is the same except for the bit about pitch adjustment.

folders are less efficient in astern but still do a pretty good job - mine can stop the boat in less than its own length from 10 knots!

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[sailorman]

we have a "Maxprop" fitted & paid for by the p.o. & its really brilliant worth every penny (deutschmark)

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[brianhumber]

I can recommend folding props, would not have a yacht with a fixed prop at any price.
Fitted a Gori three blade twin pitch and never had any regrets some 8 years ago. Still like new and gives me better thrust, lower revs, higher speeds in flat waters and much lower fuel consumption. Worth every penny.

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[Redmond]

we have a 3 bladed feathering max prop and fitted it as a replacement for a 19 year old two bladed max prop. On our old boat we had a folding prop and the max prop is much better. The old prop never squeaked but the bearing surfaces wore so much that we had excessive play and it had gone beyond the point of being reshimed. We think this is a great bit of kit if very expensive. However a Brunton feathering is a much more agricultural design and I heard that some early ones had major bearing probems with hanging blades sticking in their drooping possition

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