Propellers

[cliff]

O.K. What are the esteemed forumites opinions on folding/feathering propellers.

Folding or feathering, 2 blade or 3 blade, geared or independent blades.

Stainless steel or bronze.

Which is the best (value for money) make?
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"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>

 

[scarlett]

I have only met two people who have, while I have been with them, fitted new feathering props. [I don't know the brands ]

Both had problem with them failing to feather as designed or more likely unfeather. Whilst both companies paid for the remady/fix/repair, both had to pay for all the consequental loses including carriage. One thought his gearbox had failled and sent it away for repair, costing half the price of the prop and then pay for two lifts. The other only had to pay for one lift and two weeks in a marina, plus carriage.

There is a lot to be said for somthing simple.

 

[Sea Devil]

I had a 2 blade folding prop in my Moody 36 which was essential because the gearbox could not cope with a constantly turning prop... whilst sailing...

Once it folded (sometimes needed me to hold the shaft for a moment) it was really quiet.. I am sure it improoved performance but cannot proove it. Instint says a 2 blade folded is more efficient than a fixed prop with the shaft brake on....

Downside was going astern needed to be done slowly and was obviously much less effecient - cos the blades did not open fully .... Lots of prop walk

Would prefer to have a folding prop but I am not sure I would throw away a good fixed prop and shaft brake to buy one...

 

[davidbains]

A Kiwi prop is a pretty simple featherer really, and it has adjustable pitch. Fitted one last summer and am impressed, especially in reverse which has coarser pitch. It's cost effective, if you can say that about a £900 propellor!!!! Mind you the alternatives are even more expensive. Not much to go wrong although most skippers like me carry a spare blade "just in case", as well as the original fixed prop. The two blade folders are not good in reverse and cannot really have large well shaped blades or offer coarser pitch in reverse.

 

[Skyva_2]

I asked the same question a few months ago. Without exception those who answered preferred the one they had bought! I think they are much the same in terms of performance, and most people seemed satisfied.

After much mental agony I went for a Gori - which is undoubtedly the best /forums/images/graemlins/wink.gif . (IMVHO).
The Kiwi looked good but was not an option for my engine power. A guy on another forum reckons the drag of a a folder/featherer is about %5 of a fixed prop - he has done the drag tests and will publish the results later this year.

One other problem is that quite a few people report rapid anode erosion on Volvo props.

 

[vyv_cox]

I have been very pleased with my Brunton's Autoprop, now about five years old. It does exactly what it is supposed to do, although I doubt the saving of a half to three-quarters of a knot when sailing. Power under engine was greatly improved after installation, prop walk is reduced and speed per revs is far better. The only downside is that they are definitely not cheap. However, if you buy in Holland, as I did, they are considerably cheaper than in UK.

 

[Guest]

[ QUOTE ]
Which is the best (value for money) make?

[/ QUOTE ]
Definitely the new generation ones have more bite than the older folding CQR-type props. Just try anchoring with an old generation anchor then reverse against it at full revs with a new generation Bugel-type prop fitted and you will see the difference, unless you're in the Baltic of course.

"Nurse!!!"

 

[cliff]

I was actually considering either the Bruntons or the Steel Developments all stainless steel feathering prop. Anyone any experience of the Steel Developments one? I don't really like the idea of plastic blades so the Kiwi is a bit further down the list.

 

[cliff]

So I assume you don't rate the Rocna type prop then? I always thought it was a tarted up / rebadged Bugel type /forums/images/graemlins/laugh.gif
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"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>

 

[Guest]

[ QUOTE ]
So I assume you don't rate the Rocna type prop then? I always thought it was a tarted up / rebadged Bugel type

[/ QUOTE ]
It all depends on the type of water. The sharp tips on the Rocna prop can give it better penetration when going straight ahead but the roll bar inhibits it's ability to reset the blades when engaging astern, especially when there's too little plankton in the water. Don't believe all the traction tests you read in wikipedia!

The makers of the bugle don't blow their own trumpet enough. It's well known that most experienced sailors call a spade a Spade and stick with a CQR-type prop.

 

[mobeydick]

I was seriously thinking of the Kiwi prop, having only seen good reports, but now, on another group, I am seeing concerns on reverse pitch too corse (causing overload, even stalling of engine) and very bad fouling of the plastic blades. Is this valid or competitor 'FUD' ddoes anyone know?

An alternative I am concidering is a two blade Autoprop, which is not far off same price.

 

[davidbains]

My Kiwi blades didn't foul at all last season after giving them a light coating of hard bootop antifouling. If the engine stalls on engagement of gear either in fwd or reverse then the tickover speed is set too low. An Autoprop has more drag when sailing, but is very good at motor sailing by virtue of the automatic self pitching. The Autoprop also turns right round in reverse. The Kiwi coarser pitch in reverse should be an advantage unless you have one of the few gearboxes with the same ratio in fwd and reverse. And the Kiwi is definitely cheaper when comparing the same no of blades, and the blades align with water flow which is not the same as shaft angle.
It amuses me to now have a NZ prop and a NZ anchor!!

 

[TiggerToo]

my Kiwi did not foul either (all the blimmin critters grew on the rest of the hull instead /forums/images/graemlins/mad.gif), I put on hard A/F on the blades and some grease on the stem as suggested by the suppliers.

Kiwi it must be: great performance forward reverse and for servicing (3 minutes). And they cost less than the competitors. One down side: they certainly do not look as elegant as a brightly polished bronze three blader. But then I don't actually look at it very much when I sail!

I have also just fitted a "kiwi" anchor and it has lived up to its claims.... I am jsut waiting for another anchor troll to add my experience! /forums/images/graemlins/smile.gif

 

[Aja]

Cliff

Fitted a Gori two-blade this season. At £540 much cheaper than a Kiwi.

Admittedly reverse is not as good as when I had the fixed two-blader, but I expected that.

Can't remark on the change in sailing/speed as yet, as we've only had F2 so far, although I would say the Moody 346 seems to accelerate out the tacks more than it did before, which to be honest was s-l-o-w-l-y.

Fitted new engine, so can't really compare egges with eggs.

Donald

 

[jimbaerselman]

One thing worth puzzling over is the reliability with which your prop pitch limits can be set, or (for the Brunton) the accuracy of your usage pattern (typical cruising revs vs boat speed). A lot of assumptions go into these elements, and I know of a couple of props returned needing to be re-pitched.

There's a big reduction in this risk if either there's a lot of history for boat type and engine/gear box combinations, so the pitch setting is well known, or alternatively you've got user adjustable pitch stops.

Either way, it's worth doing your first trials in a tidal area. Much cheaper to dry out to make the changes rather than paying for a lift!