has anyone changed from fixed to folding prop with good results?

[Dazedkipper]

Changed a Volvo 15x11 fixed 3 blade prop to a Volvo 15x11 (if I recall the size correctly) folding 3 blade. Very pleased with sailing performance, most noticable in light airs. Earlier comments about engaging gear to stop spinning are correct. Only downside is the astern performance, you need more revs and applied earlier to have the desired result.

 

[srah1953]

I changed from fixed 3 blader to Flexofold 3 blader. Best thing I have done since first investing in my first Decca Navigator. I went for Flexofold over because Brunton Autoprop because latter is incompatible with sail drive. Sailing perfromance is much better and motoring/ mooring at least as good as before with very little prop walk and easy breaking
I keep a running total of distance and time and can confirm that last year I averaged over 0.6 kn faster (0ver about 1200 miles from memory) than the yeart before I fitted it.
Would definately fit a Flexofold 3 blader next time because it is best for mooring IMHO and that is the bit that stresses SWMBO out
cheers
M

I would be interested in finding out why you find the folder better than fixed for mooring

 

[Tranona]

Think you will find that the comment refers to a 3 blade folder being better than as 2 blade - not better than a 3 blade fixed. As others have said you need to recognise a delay when you go into reverse with a folder. Absolute drive is little different from a fixed prop once the blades are open. A 3 blade is usually better for motoring in both directions than 2 blade whether fixed, feathering or folding.

 

[alahol2]

Thanks to a forum member who sold me a 2 blade flexofold at a price I couldn't pass up, I very definitely have a faster boat than last year. For several years we have sailed in company with another boat. Up to this year we have pretty much matched each other in speed (give and take). This year we have walked away from our friends on every trip. It seems to be faster in all wind strengths, mainly I suspect because the boat accelerates faster out of a tack or after being stopped by a wave. I also have less turbulence over the rudder even compared to a 'skinny' 2 blade fixed. Prop walk in astern is less for some reason unknown.

 

[West Coast]

VP 2003 with sail drive, changed from fixed 3 blade vp prop to folding 3 blade vp prop. Very impressed with motoring performance, little change. Sailing performance obviously better, especially in light airs

 

[Halo]

I would be interested in finding out why you find the folder better than fixed for mooring

I meant better than Autoprop because the Autoprop self adjusts to give drive at lower revs and this is not what I want when mooring - I may want very little drive

No insult to Autoprop which I am sure is fantastic but for me the need to de -stress SWMBO when mooring is vital

 

[DaveS]

I changed from a fixed 2 blade Volvo to a 3 blade Kiwi featherer and found it very worthwhile. Under power is very slightly less efficient: with straight prop blades it cannot be otherwise, but I only notice it because I keep very detailed fuel statistics. OTOH, a definite improvement when sailing, particularly in light conditions: I think that with the Kiwi I've sailed a lot of miles when without it I'd have motored, so that more than compensates for the inefficiency issue. The variable pitch allows some experimentation, which is interesting. After a number of seasons gradually reducing pitch to the point where the engine could run at full revs at FOT, it's now courser again with FOT giving the speed for max. torque rather than max. revs which, for a displacement boat, seems much more satisfactory. No noticeable prop wash with either prop (I've a sail drive).

 

[JimC]

Changed from standard-fit Radice 2 blader to Flexofold 2 blader on Hunter Channel 31. Boat sails faster and (surprisingly) is better under power including crash stops and reversing. Believe this is because the Flexofold has much broader blades which grip the water better than the skinny ones on the Radice.

 

[Bosun Higgs]

Hi folks

I have a 3 blade fixed prop on my sail drive. I know the theory that I could gain "up to 1/2 knot" if I changed to folding prop. Has anyone succeeded in gaining this considerable increase in speed and if so could they give details of what they went for?

I would also be interested to hear if anyone found that this type of conversion resulted in any unexpected lack of power issues.

Thanks

Yes in an indirect way. I used to have a Prout cat which had a silette outdrive leg complete with three blade prop. When I lifted the leg out of the water when sailing the speed used to increase by between half anf three quarters of a knot assuming the boat was sailing at 6 knots or so in the first place. Sure that is comparing the drag of the leg itself plus prop with nothing in the water and you would be going from three blades to a folder still in the water. So maybe you wont achieve the full three quarters but you will see a significant increase. Nevertheless this is a speed comparison on the same boat on the same day in the same wind etc so its much more valid than impressions people have after changing props when they cannot say the conditions are the same

 

[RogerLS]

My boat, a Tyler Seacracker was originally fitted with 2 bladed Martec propellor. It gave me very good sailing performance but often failed to open both blades - hence damage to cutlass bearing and consequent change to 3 bladed propellor and a lessening of sailing ability in light airs.
Two years ago I fitted a KIWI feathering prop. This has given the boat back its original good performance.
The main features are
much faster sailing in light airs
much reduced noise - you don't think you are sailing fast until you look at the log.
Better pointing I think. The 3 bladed prop does create a lot of drag and noiseand hinders windward performance but I cant prove this.
Motoring performance is different. I get much less vibration due to the prop mass being concentrated at the centre. The effective pitch is greater so I get cruising speed at lower revs. This results in the engine growling rather than screaming so regrettably I tend to motor more. The KIWI has flat blades so I would expect greater fuel consumption but it is not noticeable if it exists. I have reduced the pitch once and need to do so again to suit the boat better. At present I'm limited to 2/3rds maximum revs or the engine temperature goes up to 90C.
One downside is the need to lubricate thoroughly at annual haul out. The usual greas gun is large and tends to leak grease so becomes a pain.
Overall I'm delighted with it.

 

[LynneC]

We changed *from* a Brunton folding prop *to* a 3-blade fixed because it was cheaper to buy a fixed prop than to get the Brunton serviced when we bought the boat - and with a long-keeler, the skipper (my other half) wanted his prop kick back (which he wasn't reliably getting with the Brunton). We lost masses of speed with the fixed prop, so have since had the Brunton serviced, and it's going back on this weekend! He will have to learn to live with it for close quarters manoeuvring - we need to be able to make 6 knots in the Bristol Channel to have any chance of getting anywhere against the tide. (NB. hopefully the servicing will improve the performance of the Brunton & we will end up winning on both counts. The perennial lesson - you get what you pay for.)