Folding Propeller

[ancientmariner1]

I'm thinking of replacing the prop on my 36i with either a Flexfold or a Maxprop. A claim for these props is improved maneuvering in reverse.

I understand how the such props are more efficient in reverse but I'm not clear how they will improve steering in reverse

I'd be interested in comments from any members who have made the change

Also do these props reduce prop walk in reverse?

[Deleted]

We fitted a Flexofold 3 Blade, 16X12-3R to our 36i last month.

Regarding reversing - adequate, but I am using more rpm to achieve the same stopping power as the fixed prop.
Prop Walk - almost eliminated; well and good, but I miss the prop walk to 'park' the stern when coming alongside.
Performance in forward is much improved compared to the fixed prop.

The real beauty is of course the impressive improvement in sailing performance - must be close on a knot; also a bonus - having stopped the prop rotating, the gear lever can be returned out of gear for the next engine start.

I can highly recommend the Flexofold 3 blade.

[manlyp]

I've got a Maxprop on a SO45. There are lots of benefits however there is a price to pay. They wear quickly even with proper maintenance and reconditioning and repairs are very expensive. The Maxprop is beautifully engineered but next time I would go for something simpler and harder wearing.

[Don Reaves]

The Flexofold prop is a folding prop, where the Maxprop is a feathering prop. Both give the advantage of much less drag when sailing. But in reverse, feathering props tend to give better power than folding props.

I fitted a Kiwiprop to my SO35 about two years ago, and I can't speak highly enough of it. The increased power in reverse is amazing, which means I use lower RPMs in reverse than before. The benefit to sailing is also significant. The best thing about the Kiwiprop compared with the other brands is the cost, about half.

Don

[dublin]

I fitted a kiwi on a 39. Been using it 2 seasons.
Great stopping power
much improved sailing performance.
Very simple design so very little to go wrong.
Less prop walk than old fixed 3 blade

[DUET]

I have had both the Max-Prop and Flex-O-Fold props. The Max is superior in reverse with a lot of torque. The Flex requires more rpm's in reverse, little or no prop walk. Stopping the vessel is better with the Max. However, the Flex is faster in forward motion and significantly faster, about .75 nts, sailng. Of course, the other advantage is with a folding prop, the transmission can be left in neutral. So, it's what more important to you. Both are high quality products, expensive and superior to fixed props.

[mkremedy]

ancientmariner1,
We have a 2007 36i, with a 3 blade Flex-O-Fold prop. This prop came with the boat so I cannot make a comparrison. I can only say, my next boat will come with the same prop. I find it great in revierse and there is not prop wash. The boat backs straight even at slow speeds and low rpm. In forward she will easily push the boat at 7 knots. Good Luck in trying to figure out which one is best for you.
Happy Sailing,
MKREMEDY

[CycleSailor]

I installed a 3 blade Flex-o-Fold on my SO43DS this spring, influenced among other things by test results in a UK sailing mag. We've been pretty disappointed w/the prop's performance in reverse--quite a bit of walk to port and the need to get a fair bit of way on to overcome it. I had 3 other experienced boat handlers drive the boat while I said nothing re: my feelings about the prop and all 3 had similar impressions: "wimpy". I had about 15 yrs experience w/a MaxProp on my former boat and loved it (and had none of the maintenance problems referenced on the other post). Went w/the F-o-F because of the test results and less expensive. I regret the decision.

[soulmates]

we put an autoprop on our soulmates our jeanneau ds40 - we have no prop walk and low rpms in reverse - and underway we get maybe an extra .5 to .75k underway and can maintain lower rpm - we love it

just our opinion
chuck patty and svsoulmates
currently in panama

[deandavis1]

I've got a Maxprop on a 45DS. I don't have anything to compare it to so can simply say forward and reverse are both fine... but product support is bad. I discovered a crack in the hub (less than 2 years old). Maxprop seemed to cause problems in getting it replaced under warranty. Fortunately I have a good local Jeanneau dealer who managed the process through.

[nornaj]

We installed maxprops on our two previous boats (Catalinas 30 and 34). Subsequently, put one on our SO39i, about a year after original commissioning.

+ At lower revs, the prop bites immediately in reverse and the boat tracks straight, or turns under control.
+ Still have propwalk available, just rev her up.
+ No noticeable reduction in cruising speed when motoring (but see below).
+ Speed under sail is enhanced (perhaps 0.5k).

To feather, the transmission has to be placed in reverse with the engine stopped. On our SO39i, once stopped and placed in reverse, you cannot shift the gear lever to neutral (this also undermines Yanmar's warranty - see previous post). That means re-starting in reverse, then shifting quickly to neutral.

We have had no maintenance issues whatsoever with any of the props (operating for 3 years, 8 years, and 1 year, respectively).

On one occasion only, a prop did not shift into reverse on first try. On second try with plenty of revs it was fine. As we were manouevring in the marina at the time, this was somewhat unnerving!

Otherwise, all of the issues have related to installation by professionals (??!!).

+ Forgetting to put in the locking pins (the prop shook apart).
+ An internal burr that compromised blade twist (it should have been obviously stiff on install).
+ A shaft key that was proud, which distorted the hub and impaired blade twist as soon as the bolts were hardened up (initial diagnosis was a damaged prop).
+ insistence on a courser pitch than recommended by Maxprop/distributor (performance improved when pitch softened).

The US/Canada west coast distributor (PYI) has always been prompt and fully responsive.

It is my opinion that the SO39i lacks agility at low speeds if there is any wind. On several occasions before installing the maprop, I was stuck with the boat crabbing to port/leeward in a tight situation, with

+ not enough room to turn ahead to starboard,
+ insufficient prop walk available to counter the bow's leeward shift by shifting the stern to port to increase the ahead angle, and
+ too much prop walk to allow the stern to shift to starboard and back out of the problem.

The maxprop allows me solve this by reversing out to starboard (sorry, if this is rather a poor explanation of the dilemma). Certainly less expensive than installing a bow thruster!

Finally (and wholly irrelevant) the maprop can be deployed as an original and genuinely beautiful home/office sculpture. (Those Italians do have flair.) You wouldn't do that with a kiwi or any folding prop.

NornaJ

[gre2]

Have had a KIWI prop on our SO 37 for 3 or 4 yrs. and absolutely delighted with it. Increased power in reverse, virtually no prop walk and increased performance under sail. The pitch is adjustable and excellent manual. We ordered ours from New Zealand and it arrived within a week to Canada with no problems and very easy to install. GREAT PROP

[so40gtb]

I fitted a Kiwi on the SO34.2 that we sold earlier this year and never regretted it. Our SO40 came with a Maxprop and I have nearly no issues with it. The Max bites harder in reverse than does the Kiwi, but both are far better than any fixed prop. The Max is more easily fouled by marine vegetation, but is usually readily freed by reversing and gentle revving. The Kiwi has less prop walk, but I've used the Max's initial walk to great advantage in several "tight" situations. Both track straight back once moving. Can't speak to the folders, though most of the serious racers use them.