Derekrules69
New Member
I have a Jeaneau 39 powered by a Yanmar 40HP and would like to switch from the standard 3 Blade prop to either a feathering or folding prop. Does anyone have any advice I can use? Thanks.
Feathering or Folding Prop?
- Thread starter Derekrules69
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savageseadog
Well-Known Member
I think folders are generally lower tech and less likely to catch stuff when sailing. But the Kiwiprop is the best prop although it's a feathering one, doesn't corrode.
Sailfree
Well-Known Member
A previous post but i believe the points are still relevant.
I have just gone through the same decision loop. Its also aggrevated in my case with the new Yanmar insisting locking gearbox in astern while sailing stresses the gearbox - it also locked the gearbox in astern and had to be started that way before being able to change to neutral.
1. Folding - least resistance of all
-poor power astern
- on most boats worth an extra 1/2 to 3/4 knot when sailing
2. Feathering- slightly more resistance than folding.
- more power astern than even a fixed prop (blades reverse direction for max efficiency). For most boats/engines will stop a boat in astern in its own boat length from 6kts.
- again worth an extra 1/2 to 3/4 kts when sailing
3. Bruntons (forget name) initially need more wellie to get power astern. I was also not keen on the amount of bearings exposed to salt water/marine growth.
I chose a feathering prop. Of these
a) Kiwi prop looked good reasonable price and would be of interest except maximum power handling ability. Plastic blades hence cheapness but for small boats I would have seriously considered them. pitch adjustable forwards but fixed for astern - some problems reported but many think they are OK.
b) Aquastream interesting as in stainless steel and warranteed for 5 yrs but one of dearest
c) Maxiprop- good but cannot adjust pitch from outside and needs to be assembled and pitch adjusted when installed - quite dear and often better with even dearer larger hub option.
d) Variprop - Can adjust pitch from outside, already assembled can slide on, has a 2,3 or 4 blade option for larger engines. has an internal cushion effect for when going forwards to astern and vice versa. cheaper than the maxiprop & Aquastream
My decision - having checked the market I decided the variprop was technically superior although was tempted with the SS aquaprop meaning no disimilar metals on shaft. I had bought a Variprop before on my previous boat and was happy with it but admit I had done a lot less research then. I finally got a good deal - Variprop can be supplied through a number of suppliers (pm me if you are serious)
Bear in mind my requirement are for heavy use on the charter market, cannot have any idiosyncasies as must be idiot proof (hence Gori prop and Bruntons were out). The advantage of quickly stopping the boat if misjudging a berthing situation was a big plus.
Must add 1st boat had a Volvo folding prop which was replaced 3 times under warrantee. Product IMHO not robust enough for charter market but OK for average owner for a few years. Full marks to Volvo for replacing it FOC but lost money on lost charters though.
I have just gone through the same decision loop. Its also aggrevated in my case with the new Yanmar insisting locking gearbox in astern while sailing stresses the gearbox - it also locked the gearbox in astern and had to be started that way before being able to change to neutral.
1. Folding - least resistance of all
-poor power astern
- on most boats worth an extra 1/2 to 3/4 knot when sailing
2. Feathering- slightly more resistance than folding.
- more power astern than even a fixed prop (blades reverse direction for max efficiency). For most boats/engines will stop a boat in astern in its own boat length from 6kts.
- again worth an extra 1/2 to 3/4 kts when sailing
3. Bruntons (forget name) initially need more wellie to get power astern. I was also not keen on the amount of bearings exposed to salt water/marine growth.
I chose a feathering prop. Of these
a) Kiwi prop looked good reasonable price and would be of interest except maximum power handling ability. Plastic blades hence cheapness but for small boats I would have seriously considered them. pitch adjustable forwards but fixed for astern - some problems reported but many think they are OK.
b) Aquastream interesting as in stainless steel and warranteed for 5 yrs but one of dearest
c) Maxiprop- good but cannot adjust pitch from outside and needs to be assembled and pitch adjusted when installed - quite dear and often better with even dearer larger hub option.
d) Variprop - Can adjust pitch from outside, already assembled can slide on, has a 2,3 or 4 blade option for larger engines. has an internal cushion effect for when going forwards to astern and vice versa. cheaper than the maxiprop & Aquastream
My decision - having checked the market I decided the variprop was technically superior although was tempted with the SS aquaprop meaning no disimilar metals on shaft. I had bought a Variprop before on my previous boat and was happy with it but admit I had done a lot less research then. I finally got a good deal - Variprop can be supplied through a number of suppliers (pm me if you are serious)
Bear in mind my requirement are for heavy use on the charter market, cannot have any idiosyncasies as must be idiot proof (hence Gori prop and Bruntons were out). The advantage of quickly stopping the boat if misjudging a berthing situation was a big plus.
Must add 1st boat had a Volvo folding prop which was replaced 3 times under warrantee. Product IMHO not robust enough for charter market but OK for average owner for a few years. Full marks to Volvo for replacing it FOC but lost money on lost charters though.
Derekrules69
New Member
Thanks for that. It also has the benefit of being sub £1000 so its high on the list. Many thanks for your input, much appreciated, Derek
Derekrules69
New Member
Now that is interesting. I had no idea there was that restriction on the gearbox although once during a 'senior moment' I did accidentally put it in astern whilst sailing, jammed it up and had to start it to free it off. Thanks for all the info and advice, truly appreciated, Derek
sailorman
Well-Known Member
imho i have a 2 bladed MaxProp it is very good & would recomend them
P.S. Oyster fit them as Std
P.S. Oyster fit them as Std
Tranona
Well-Known Member
There was a good review come "test" in YM a couple of months ago.
Think you need to be clear about what your aims are in making the change. The basic characteristics that Sailfree list are correct, although the YM article shows that specific designs do not always fit the generalities. I suspect also that some of the performance "improvements" reported by some owners reflect their desire to justify the expense rather than reflect reality.
Fixed blade propellers tend to give the best compromise motoring performance with simplicity and reliability. On a typical cruising boat, there may be other ways of improving sailing performance that are more cost effective.
Feedback from owners of all kinds of propellers garnered from my professional activities are inconclusive, except that owners of Bruntons Autoprops who motorsail a lot, particularly in the Med seem to support the claims for that design.
Does not really help. However, I have two boats, one with a feathering prop (a Darglow Featherstream) where I get the promised performance - mainly improving sailing performance on a heavy old long keel boat: The other has a Volvo Saildrive but I stick to the standard fixed 2 blade, partly because of the performance in reverse and partly because of all the maintenance and corrosion problems I have seen over the years, particularly folding propellers.
Think you need to be clear about what your aims are in making the change. The basic characteristics that Sailfree list are correct, although the YM article shows that specific designs do not always fit the generalities. I suspect also that some of the performance "improvements" reported by some owners reflect their desire to justify the expense rather than reflect reality.
Fixed blade propellers tend to give the best compromise motoring performance with simplicity and reliability. On a typical cruising boat, there may be other ways of improving sailing performance that are more cost effective.
Feedback from owners of all kinds of propellers garnered from my professional activities are inconclusive, except that owners of Bruntons Autoprops who motorsail a lot, particularly in the Med seem to support the claims for that design.
Does not really help. However, I have two boats, one with a feathering prop (a Darglow Featherstream) where I get the promised performance - mainly improving sailing performance on a heavy old long keel boat: The other has a Volvo Saildrive but I stick to the standard fixed 2 blade, partly because of the performance in reverse and partly because of all the maintenance and corrosion problems I have seen over the years, particularly folding propellers.
Sailfree
Well-Known Member
[ QUOTE ]
I suspect also that some of the performance "improvements" reported by some owners reflect their desire to justify the expense rather than reflect reality.
[/ QUOTE ]
Agree wholheartedly.
Just to be clear a shaped fixed propeller properly sized will give trhe best forward speed when motoring. Shaped blades become inefficient trying to go astern. When people try to state that their brand "x" propeller is better than the manufacturer supplied orginal - doubt their objectivity.
Propellers are like boats most have good point and some bad- they are all a compromise.
I suspect also that some of the performance "improvements" reported by some owners reflect their desire to justify the expense rather than reflect reality.
[/ QUOTE ]
Agree wholheartedly.
Just to be clear a shaped fixed propeller properly sized will give trhe best forward speed when motoring. Shaped blades become inefficient trying to go astern. When people try to state that their brand "x" propeller is better than the manufacturer supplied orginal - doubt their objectivity.
Propellers are like boats most have good point and some bad- they are all a compromise.
TiggerToo
Well-Known Member
[ QUOTE ]
I suspect also that some of the performance "improvements" reported by some owners reflect their desire to justify the expense rather than reflect reality
[/ QUOTE ]
Absoluetly correct. I have bought a Kiwi Prop and since it was the chapest and delivers a significant improvement on the 2 blade fixed prop, I will argue strenuously that it is the beesknees. /forums/images/graemlins/ooo.gif
Although it will not win the aesthetics poll, its functionality, the ease of service/maintenance, the rock bottom cost of replacing a blade (if you need one - not a common occurrence) make it one of the best purcahses adn upgrades Tigger has had...
And, yes, Alan and Gabrielle Pollard of Vecta Marine (importers & distributors in the UK) are an absolute delight to deal with.
I suspect also that some of the performance "improvements" reported by some owners reflect their desire to justify the expense rather than reflect reality
[/ QUOTE ]
Absoluetly correct. I have bought a Kiwi Prop and since it was the chapest and delivers a significant improvement on the 2 blade fixed prop, I will argue strenuously that it is the beesknees. /forums/images/graemlins/ooo.gif
Although it will not win the aesthetics poll, its functionality, the ease of service/maintenance, the rock bottom cost of replacing a blade (if you need one - not a common occurrence) make it one of the best purcahses adn upgrades Tigger has had...
And, yes, Alan and Gabrielle Pollard of Vecta Marine (importers & distributors in the UK) are an absolute delight to deal with.
charles_reed
Well-Known Member
<<3. Bruntons (forget name) initially need more wellie to get power astern. I was also not keen on the amount of bearings exposed to salt water/marine growth.>>
It's called an Autoprop.
After 18 years of using one, after a folding prop and a fixed 3 blader on the same boat. I'd comment as follows:_
1. The Autoprop needs to be locked in forward gear - this proves no problem with the Yanmar gearbox (I've a 3YM).
2. It's extremely unwise to use more welly in reverse, you'll lose your crew off the foredeck - there is a delay, it takes about 3 revs before the blades fully rotate and bite, if you allow for that the Autoprop is infinitely superior to a fixed prop.
3. Mine is an early one, it's needed a new set of bearings after 14 years and about 45,000 miles of use. Only once has fouling interfered with setting, after leaving the boat for 8 weeks on summer in the Dovey - a quick burst ahead and reverse soon cleaned it.
4. The bearings do need regular resetting (about every 500 hours of use) or the whole thing gets noisy and rattles
To be accurate the Brunton is NOT a feathering, but a self-pitching prop, (as, I believe, is the Kiwi) it's self-pitching facility makes it ideal for motor-sailing and for plugging a head sea and heavy wind. It does have to be carefully tuned to the torque curve of the engine and the slipperiness of the hull.
As you know a fixed prop can only be ideal at a certain power output and resistance and has only simplicity and low cost going for it.
Variprop and maxiprop are really feathering props with a variable pitch which can be operator set.
You have forgotten to mention the Hunstedt, the grandaddy of all the variable pitch propellers, in use from the end of the 19th century and still occasionally fitted to leisure vessels. At one time 60% of N Sea FVs had them and many dispensed with F/R gearboxes.
With regard to the assumptions you make some, especially re drag, would appear to be contradicted by published research by the Wolfson Institute - the Maxi-Prop came out as the most slippery of low-drag props, with the two-bladed folding prop being surprisingly cumbersome at certain speeds.
It's called an Autoprop.
After 18 years of using one, after a folding prop and a fixed 3 blader on the same boat. I'd comment as follows:_
1. The Autoprop needs to be locked in forward gear - this proves no problem with the Yanmar gearbox (I've a 3YM).
2. It's extremely unwise to use more welly in reverse, you'll lose your crew off the foredeck - there is a delay, it takes about 3 revs before the blades fully rotate and bite, if you allow for that the Autoprop is infinitely superior to a fixed prop.
3. Mine is an early one, it's needed a new set of bearings after 14 years and about 45,000 miles of use. Only once has fouling interfered with setting, after leaving the boat for 8 weeks on summer in the Dovey - a quick burst ahead and reverse soon cleaned it.
4. The bearings do need regular resetting (about every 500 hours of use) or the whole thing gets noisy and rattles
To be accurate the Brunton is NOT a feathering, but a self-pitching prop, (as, I believe, is the Kiwi) it's self-pitching facility makes it ideal for motor-sailing and for plugging a head sea and heavy wind. It does have to be carefully tuned to the torque curve of the engine and the slipperiness of the hull.
As you know a fixed prop can only be ideal at a certain power output and resistance and has only simplicity and low cost going for it.
Variprop and maxiprop are really feathering props with a variable pitch which can be operator set.
You have forgotten to mention the Hunstedt, the grandaddy of all the variable pitch propellers, in use from the end of the 19th century and still occasionally fitted to leisure vessels. At one time 60% of N Sea FVs had them and many dispensed with F/R gearboxes.
With regard to the assumptions you make some, especially re drag, would appear to be contradicted by published research by the Wolfson Institute - the Maxi-Prop came out as the most slippery of low-drag props, with the two-bladed folding prop being surprisingly cumbersome at certain speeds.
rwoofer
Well-Known Member
I used to have a max-prop on my old boat and now have a flex-o-fold two blader. Both are excellent props. What really surprised me is that the flex-o-fold is great in reverse and better than any fixed prop I have used. The max-prop was exceptional in reverse with the added advantage that you can change the pitch.
I chose flex-o-fold in current boat as it offered minimum resistance and was a lot cheaper than a max-prop. Both flex-o-fold and max-prop are at the premium end, so I think reputation is possible more important than whether folding or feathering.
I chose flex-o-fold in current boat as it offered minimum resistance and was a lot cheaper than a max-prop. Both flex-o-fold and max-prop are at the premium end, so I think reputation is possible more important than whether folding or feathering.
Vamoose
Well-Known Member
As someone else said YM did a very good test on a variety of props a couple of months ago and they concluded that sailing with a 3 bladed fixed was similar to towing a bucket !
I changed my 3 bladed fixed for a 2 bladed folding Bruntons Varifold which the YM tests concluded gave one of the best results of all the props tested for thrust ahead (as good if not better than a 3 bladed fixed) ... Virtually no drag when sailing (Its put the best part of a knot on my boat).. But to go astern you need to whistle down to the engine room well ahead of when you want something to happen, as it takes tome to bite ! .... On my boat prop walk is no better or worse than the 3 bladed fixed.
Before purchase I did a lot of research and narrowed it down to the Kiwiprop or the Varifold.. I am delighted with my choice which was confirmed by reading the YM Tests
PS Do not mix up the Bruntons Varifold & Bruntons Autoprop they are 2 different products
I changed my 3 bladed fixed for a 2 bladed folding Bruntons Varifold which the YM tests concluded gave one of the best results of all the props tested for thrust ahead (as good if not better than a 3 bladed fixed) ... Virtually no drag when sailing (Its put the best part of a knot on my boat).. But to go astern you need to whistle down to the engine room well ahead of when you want something to happen, as it takes tome to bite ! .... On my boat prop walk is no better or worse than the 3 bladed fixed.
Before purchase I did a lot of research and narrowed it down to the Kiwiprop or the Varifold.. I am delighted with my choice which was confirmed by reading the YM Tests
PS Do not mix up the Bruntons Varifold & Bruntons Autoprop they are 2 different products
Sailfree
Well-Known Member
I think that Varifold and Variprop (feathering)are made by the same German company. Bruntons market the varifold but not sure they market the variprop as they would argue that their Autoprop is better.
I agree that the Autoprop is very good at motorsailing due to self pitching aspect and suspect it is the one prop that could be more efficient that the standard fixed prop as it will adjust its pitch to suit conditions (calm or rough).
For a charter boat I needed it simple and either the delay in engaging astern or the need for more wellie is unacceptable. Some charter skipper are not so experienced and I needed instant max power astern for either a misjudged berthing or a sally onto the putty and a feathering prop is best for this.
I agree that the Autoprop is very good at motorsailing due to self pitching aspect and suspect it is the one prop that could be more efficient that the standard fixed prop as it will adjust its pitch to suit conditions (calm or rough).
For a charter boat I needed it simple and either the delay in engaging astern or the need for more wellie is unacceptable. Some charter skipper are not so experienced and I needed instant max power astern for either a misjudged berthing or a sally onto the putty and a feathering prop is best for this.
Vamoose
Well-Known Member
Visit Bruntons Propellers for details of Bruntons Varifold & Autoprop.
tri39
Well-Known Member
I chose a Kiwi prop on grounds of simplicity and cost and that it's a three blader with adjustable pitch. Last and by no means least is the coarser pitch in reverse which is wonderful when your gearbox has a higher ratio in reverse. I would not like to go back to a fixed two blader now.
In fact last summer the Kiwi prop in instant reverse saved the skull of an inebriated idiot in an inflatable. (Approaching on the port bow I hasten to add!)
In fact last summer the Kiwi prop in instant reverse saved the skull of an inebriated idiot in an inflatable. (Approaching on the port bow I hasten to add!)
BlueChip
Well-Known Member
[ QUOTE ]
I used to have a max-prop on my old boat and now have a flex-o-fold two blader. Both are excellent props. What really surprised me is that the flex-o-fold is great in reverse and better than any fixed prop I have used. The max-prop was exceptional in reverse with the added advantage that you can change the pitch.
I chose flex-o-fold in current boat as it offered minimum resistance and was a lot cheaper than a max-prop. Both flex-o-fold and max-prop are at the premium end, so I think reputation is possible more important than whether folding or feathering.
[/ QUOTE ]
I've got a flexofold 3 bladed folding prop and I'm very happy with it.
Does everything I ask of it and provies oodles of push, both forward and reverse and at cruising speed I only need just above 2000 revs
I used to have a max-prop on my old boat and now have a flex-o-fold two blader. Both are excellent props. What really surprised me is that the flex-o-fold is great in reverse and better than any fixed prop I have used. The max-prop was exceptional in reverse with the added advantage that you can change the pitch.
I chose flex-o-fold in current boat as it offered minimum resistance and was a lot cheaper than a max-prop. Both flex-o-fold and max-prop are at the premium end, so I think reputation is possible more important than whether folding or feathering.
[/ QUOTE ]
I've got a flexofold 3 bladed folding prop and I'm very happy with it.
Does everything I ask of it and provies oodles of push, both forward and reverse and at cruising speed I only need just above 2000 revs
Sailfree
Well-Known Member
For completeness.
Variprop are the only one that does a 4 blade feathering prop. Very smooth on my 75HP Yanmar.
Variprop are the only one that does a 4 blade feathering prop. Very smooth on my 75HP Yanmar.
Tranona
Well-Known Member
Interesting Max Prop brought one out a couple of years ago specifically for the biggger Oysters, but I see it has disappeared from the catalogue.
geoffcollins
Well-Known Member
I bought a 2 blade Bruntons Varifold for our Sweden 36.
I've summed up my thoughts on the various players here: http://sweden36.blogspot.com/2009/02/propeller-decisions.html
I've been really impressed with the performance in terms of drag, power ahead and particularly power astern.
I've summed up my thoughts on the various players here: http://sweden36.blogspot.com/2009/02/propeller-decisions.html
I've been really impressed with the performance in terms of drag, power ahead and particularly power astern.
Paul_Carroll
New Member
You can sometimes find used Autoprops at sub-1000 prices if you look around. There is one listed on the Annapolis Craig's List. These really are amazing props!