Folding Propellers

S

Sailfree

Well-Known Member
Joined
18 Jan 2003
Messages
21,696
Location
Nazare Portugal
Visit site
I am thinking of going the folding propeller route and am surprised by the price differential. I don't necessarily assume dearest is best.

Gori £1750 + 2 anodes every lift out at £47 therefore £94pa

Flexifold £1060 + 2 @£25 anodes is £50pa

Varifold ££880 + 2 @ £15 is £30pa

It will be going on a charter boat so durability is an issue. Do anyone have an experience or comparisons

Rumour has it that the Gori has superior astern power but can suffer vibration and is not simple to pull off the shaft. The Flexifold was designed by the same person who designed the Varifold but with improvements.

Does anyone have any analytical articles or comments. I have the Sailing Today May 2001 article but its more superficial than analytical and critical.
 
Have a long hard look at the Kiwiprop. retail £795 +VAT and is next on my list (Jen SO35). I bought the pretty Cruising Chute this year instead.
Is a feathering 3 blade with good performance back and forward, and feathers to lowest resistance - without gears.
Anodes on a plastic prop?

AlexL has one on his Hanse 371 and is delighted.
We are both Engineer Gadget freaks. Hands Up to that.

http://sdmarine.co.uk/sdmarine/sdmarine_4.html
 
Is the Kiwiprop plastic then? I wonder if durability would be an issue. Do Kiwiprop make 3 blade as engine is 75hp so it needs to have take the thrust?

Whats astern power like? While many of the skippers would be better sailors than me a few may be relatively inexperienced and I can't have something that they have to take account of - like lots of wellie before it goes astern.
 
The answer is yes most charters are very keen sailors and really appreciate the extra sailing speed. Many charters maximise use of the boat so its often off France and the current cheap 3 bladed prop has picked up 2 fishing nets in the last month. I know a folding prop can still pick up fishing nets but feel the risk is reduced when sailing.

I want the best for them and they respond by repeat bookings.
 
Don't forget Autoprop, folding and self-feathering bronze, one anode per yr approx £20. Excellent astern, and great for motorsailing if late for tidal gate in light wind etc. Mine's been good for 6 years.. just had the bearings replaced (appprox £100).
 
Have had a 3 blade Gori on for over 20,000 miles and several hundred hours motoring. Best investment I ever made, cuts revs, noise and vibration in overdrive and yes the astern power is great. Far better than others I have had over the years.
After 5 years had to remove to change p bracket bearing and so well engineered only took 10mins to get main hub off, grease still inside the cone.
I note you are a charterer owner, the only note of caution I would raise is will charters slam from ahead to astern too roughly to get the overdrive and will they drop down when the sea gets up. You could get higher box wear than normal.

B
 
I have the 3 bladed folding Gori. Chosen because it was the only viable option for what is quite a difficult installation on my boat.

It is a stunning piece of kit - as good as a fixed prop in forwards and better than anything in reverse.

The only downside is the cost (both initial and on-going). If money is no object it is probably the best propellor on the market - whether it is value for money is a different matter
 
Hi,

Ive run tests on the saildrive equivalent of the Gori 2 blade 16x11 and Kiwi composite (and others but not on your list) the Kiwi came out on top of all the tests but i'm yet to publish any of the data. Gori's even with Anodes (you will find often anodes are not big enough to last a typical season) have serious durability issues (esp in marinas with known electrolysis issues) the teethed gear ware quickly and the baldes jump. The Kiwi however has no or very little corrosion issues (Small surface area of metal (alloy bronze hub, with composite blades) it does however have very slighty more resitance due to it being a feathing propeller. However the power into the water is impressive, reversing is superb (though on a small yanmar (2gm20fc) you have to make sure your warmed up before push back otherwise it will tend to stall in reverse as pitch is maximised when you engage reverse and hence lots of load). From the tests i've conducted the kiwi is the best prop from durability (corrosion), its a third of the mass as one of the standard alloy bronze (gori etc) so easier on your shaft bearings, power into the water is superb and its fantasic value for money.... Send me a pm if you want any further info on either the gori or the kiwi...

The picture below shows the problems you would face with the standard props unless your boat is perfectly sound electrically - which if you are in a marina is never the case - Photo is of Gori 16x11 2 blade nickle alloy bronze sail drive prop after durability tests:

Goribladesmall.jpg
 
Thanks for reply.

First boat I had was fitted with a Volvo folding prop. Volvo at least then lived up to their obligations and replaced it 2 times (when it gave problems within a year) they then gave me my money back and suggested I fit any other propellor except theirs. I concluded that this volvo folding prop would be acceptable for a normal owner with say 60hrs per year but not a charter boat with say 500hrs! I would also comment that my experience was on a folding 2 blade, I believe their 3 blade is different. However after my most recent dealings with them I concluded that their response now to any warrantee claim is shall we say unhelpful or "robust" (a term used by the boat distributor) and they deny everything saying (in my case) boat just overheated. Unfortunately I have heard of a few of their 3 cylinder engines seizing at low hours that combined with their attitude I chose my last boat firstly on the basis of excluding ALL makes of boats with Volvo parts. So sorry but based on my personal experience even if a 3 blade Volvo was the best I would not consider it.

I am sure many others can write that their Volvo engine/bits has been OK but I can only go from my experience and others in the charter market where if there are any weaknesses they are found more quickly.
 
My understanding is that the Brunton Autoprop needs more wellie than most before it developes power to go astern. Also even when not in use the blades are fully exposed to pick up fishing nets.

I remember Andrew Bray of Yachting Monthly fitted one to his new yacht Firefly. Can't remember the details but I think he had some issues with it but never heard whether he got them resolved.

One kind scuttlebutt reader send me a fantastic comparison chart which I think was translated from a German magazine Very analytical but dated 1997 and I am not sure whether the props referred to are the ones still in production.

The Bruntons Autoprop came out top for thrust at 5.44kn developing 871N, Fixed prop 762N, Gori 635N(873 overdrive), Maxprop 430N, Sailprop371N, Variprop437n & Volvoprop565N, I can comment further than the useful table e mailed me as I have no other details of the circumstances of the test nor the acuracy of the translation but it looked a really good scientific anaylsis and I wish UK mags did better tests rather than bland articles.
 
You must log in or register to reply here.

Share this page

Top