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Closet Powerboater
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Discussion Starter · #1 ·
Some of the boats I am looking at buying have a Max Prop. One of these puppies was historically never in my price range, so I never learned much about them.

My limited understanding is that they fold the blades when sailing to reduce drag under sail (a good thing) and that they reverse the blade pitch in reverse to increase power in reverse (a good thing) and that they are expensive and add complexity and possibly more failure points (a bad thing).

Is the above generally true? Is there more to it than that? Does one loose efficiency in forward? Do they constantly adjust pitch at different RPMs or are they "fixed pitch" when operating? Do they help with prop walk?

Thanks. As you can see, I don't know much about these props, so any advice or opinions would be useful.

MedSailor
 

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the pointy end is the bow
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6,264 Posts
We have one on Nikko. Came with the boat. Sometimes it takes a couple tries to feather the prop when we transition from motoring to sailing. They don't have hardly any prop walk which I actually kind of miss. I can't keep the cone zinc on it for more than six to nine months. When they start to wear, the bolts that hold it on get loose and it throws itself off. We keep the shaft zinc'ed as well, so I don't worry too much about electrolysis. It's the only feathering/folding prop I've had, so I can't compare it to other props. I've been told that it has much better reverse performance that folding props.
 

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I have a 25 year old model. I had it reconditioned this winter. PO did not keep records, so I have no idea when it was last done. (Manual said 1997!) Cost was about $400. I've never had another prop on this boat, but I'm very happy with it. There are not a lot of moving parts, so I would think failure is highly unlikely unless you hit something.

The newer ones can be adjusted while on the boat. Mine needs to be disassembled on the hard. Good luck with the search!
 

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bell ringer
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5,564 Posts
I had a MaxProp on my last boat and when I got my current one was going to get another feathering prop. But after research decided based on all the tests I could find that the "advantages" of a feathering prop over a folding prop were pretty minor almost to the point of make believe. So I got a Flex-O-Fold prop instead. Based on my experience the differences are:
- the Flex-O-Fold was over $1000 less expense
- the Flex-O-Fold is way less complex
- the Flex-O-Fold seems to be just as good in reverse (what is suppose to be the advantage of the MaxProp)
- the Flex-O-Fold is WAY more efficient in forward and uses a LOT less fuel for the same boat speed even though it is on a bigger boat
- the Flex-O-Fold doesn't need maintenance other than new zincs

In the end I wanted to reduce drag while sailing, have the least complex prop to do it, spend the least amount of money, have reasonable power and control in reverse; the Flex-O-Fold 3 blade prop I got did all these for me.
 

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Irrationally Exuberant
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I was lucky enough to have the previous owner spring for my MaxProp. Yes, more complex than standard, but it seems like a very solid, relatively simple piece of gear. Maintenance consists of refilling with grease through the grease port every two years.
 

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We had a 2-bladed folding on the last boat, and a 3-blade max-prop on the current, both courtesy of the previous owners. The most noticeable difference for me was the performance in reverse. Really quite an amazing difference. Mine definitely has some prop walk, although less than the old folder.

As for the cone zinc, apparently there are two versions available. On the original (and still commonly available) version, the zinc around the bolts is sacrificed quickly causing it to loosen up as noted above. The improved version has reinforcement using a different metal near the bolts to reduce that problem. This is my first of the improved zinc, so we will see.

Mine required about $700 in rebuild cost at 10 years old. I don't know if it was serviced before that (besides the yearly grease) but I imagine it was not.
 

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Im DELIGHTED with the performance of my (short hub) Max-Prop.
Ive 'repitched' several times and can state emphatically that my engine is now 'maxed' because of the Max Prop, etc. etc. etc.

Only downside, is that the blades do become 'wobbly' after a few years (due to reversing/forwarding) ... but ~$400 is a reasonable cost to 'rebuild'.
The 'improved' cone zincs are TERRIFIC - long lasting.
 

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Master Mariner
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9,220 Posts
I have used a number of folding props in the past and generally was unhappy with their performance under sail or power. However, this boat came with a complete MaxProp, in a bag, and I decided to try it out.
It is absolutely marvelous. No longer do I need the hydraulic shaft brake, and the wheel isn't spinning for hours at a time, under way. It feathers easily and if it's cranky (if we're sailing above 7 knots, sometimes it won't feather), just shut down in forward and it always feathers then. Unlike most folding props, the MaxProp does not rely on centrifugal force to open; it has gears which force the blades open, in both forward and reverse, so it should (it hasn't in 3+ years) never fail to open, and it will not fold when motorsailing.
As mentioned above, with a lot of use, it does need the occasional servicing from the factory, but don't you have to have a fixed prop balanced every so often, as well?
 

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I switched from a fixed prop to a Featherstream prop a few months ago. I also considered the Max-Prop and Flex-O-Fold. The Featherstream and Flex-O-Fold prices were very similar and the Flex-O-Fold agent was very unhelpful. The Featherstream agent was extremely helpful, as was PYI when I asked about the Max-Prop.

The Featherstream is made by Darglow, the UK Max-Prop importer. It is very similar to Max-Prop, but pitch is adjusted differently. I've also sailed on boats with a Max-Prop and helped a friend adjust a 3-blade one.

The sailing performance improvement is great. It is easy to measure, if you leave the engine in neutral after going forward the prop will freewheel just like a normal bladed prop. Put it into reverse to lock the blades and in normal sailing conditions the boat will speed up by half a knot to a knot depending on the wind conditions. That is a great improvement!

I haven't done enough cruising on the Featherstream to see how fuel economy will compare to my previous Campbell Sailor prop. I don't notice any difference in motoring performance and have never had trouble getting the prop to go into forward or reverse.

The devices are pretty simple internally and as long as they are kept lubed I see little that can really go wrong. I do have an old 2-blade prop that I will carry onboard as a spare when cruising. I doubt that I'll ever need it, but it provides a bit of peace of mind and doesn't take up much space.
 

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I installed a new max prop on my boat in 1985 and it has served me well over those years. Every 2 to 3 years when I haul the boat, I repack the gears with grease and I usually need help in doing that. Many of the newer ones have zirks fitting so that grease can easily be added without disassembly. Also there may be easier ways on newer models to adjust the pitch rather than complete disassembly which I have to do if I want a new pitch. The pitch adjustment allows some fine tuning to hit a sweet spot on the engine rpm, however note that the pitch is constant once set and an variable pitch prop would be a better performer, but is more complex. Besides having the advantage of experimenting with pitch, the reverse thrust is a huge advantage when docking. I also still have prop walk which someone else said they did not. I consider prop walk as a advantage. There is some loss of efficiency in forward since the blades are flat vs a curved blade of the fixed prop. Not sure how significant that is.

I'm happy with the performance and have noticed recently some wobble in the blades and did not know that maybe that can be improved. Not bad for close to 30 years of use including some ICW motoring trips.
 

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I have a two blade Autostream feather prop which looks similar to the Maxprop. The prop was already on the boat and it works fine, solves the problem of the prop turning, which always worried me on my last boat. Only issues I had was when I installed a new engine we had to play with pitch to get the engine revs / boat speed working properly. This was pretty easy to adjust whilst in the water, did it in 5 minutes. Only other problem is occasionally the props get stuck in place and do not feather when you switch the engine off and go back to sailing (you can hear the shaft turning). Its easy to fix, you slow the boat and place the engine in reverse and it fixes the problem. (Probably barnacles or seaweed catching).

They are expensive, however would definitely recommend if your budget stretches that far. Plus it resolves the issue of the prop constantly turning.

Ilenart
 

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I put a 2-blade Maxprop on my previous boat and was very happy with it. Power in reverse was great and there were never any problems with the blades opening/closing. I did not have it long enough to comment on the longevity. The company was very responsive during and right after the sale. I expect that would continue if the prop ever needed service.

My current boat came with a Flexofold. Nice, but has almost no prop walk. My previous boat with the Maxprop had some prop walk, and I miss not having it.

Yachting Magazine had a review of various props which you might find interesting. (As with any review, I'd take it with a grain of salt and an understanding this is just one data point.)

http://www.flexofold.com/upload_dir/docs/Test_YachtingMonthly_low.pdf
 

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Our Max Prop is now ten years old and has performed like a champ. As mentioned, it feathers (twists parallel to the direction of the boat to reduce drag) when not being turned by the motor. If it doesn't do it on its own, after you shut down and are moving under sail, just briefly put the transmission in reverse and then back to neutral. Folding props, by comparison, have blades that lay down to reduce drag. That seems unnatural and more complex to me, although, that's not a very scientific argument.

Mine has held up with no wobbling in the blades. I did hit something submerged a few years back and put a good whack in the leading edge of one blade. I didn't even know it until I hauled for the season. I believe that some systems would have torn the blade off or broken the feathering/folding prop.

I took the unit off the shaft and mailed it back to PYI. They repaired it, cleaned it all up, rebalanced the entire unit and sent it back looking brand new for a few hundred dollars. Service was excellent! When removing from the shaft, the heavy duty build quality was very noticeable.

Finally, older models have two internal settings to get the pitch correct. It's very important that you are able to reach, but not exceed, your engines max rpm at wide open throttle under load, which is a function of prop pitch. Amazing how many are set incorrectly (on all makes and models of props), and owners can't figure out why they have engine trouble. In rare cases, you find you need to readjust by one notch upon initial assembly, which would require hauling. Maybe there is a diver than has the guts to do it under water, but there are several parts. Once right, you never touch it again, other than to grease every two years (I do so each winter)

Newer models can have their pitch adjusted from the outside, but once you get it right, you're unlikely to ever need to touch it again.
 

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My PO put on mine, one year's experience with it.
I love it, no prop walk at all, which has good and bad sides. Good is that it is consistent and you can back both to port and starboard equally. Bad is you can't use prop walk to help you.
It does have more power in reverse, never a bad thing to have.
 

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Oh yea. We back into our pier side slip, down a fairway and "parallel park" between two other boats. Reverse performance is terrific. Once I get her moving in reverse, I just pull the throttle back to idle and she creeps along nicely. No need to muscle the prop in reverse.
 

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Have had it on my last 2 boats, including current. As pointed out by others, it has as we say in Boston a "wicked good reverse."

At least on my boat, it hasn't taken away the walk. We have a skeg hung rudder.

There is definitely more to go wrong, but in 15 years of experience on 2 boats, we haven't had any problems.
 

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We have a max prop, and it works just fine. But I wish I had a flexofold folding.

A feathering prop has no "twist". And, unless your prop shaft is level, then there will be drag from the downward angle. The flexofold is twisted like a more efficient propeller. And, you can't beat folding props for low drag. I hear no problems in reverse either.

On a sailboat, motoring efficiency is critical. The flexofold is pretty hard to beat in this regard.
 

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If one is having issues getting a max to fold per say, one must be over 3 knots or so when you shut the motor off, or the ability to sail at over 3 knots. putting the gear **** is reverse after shutting off will also help it get into folded mode!

A gain of .75-1 knot of boat speed while sailing is common wording for those that went from fixed to a max, or any folder/feathering prop frankly. A max prop is heavy vs other styles, and seems to use a bit more fuel while motoring because of this. But my MP thanks to previous owner also, has all the attributes mentioned by others.

Marty
 

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We have a 3 blade Classic, it's been very good and reliable for the past 13 years. We sent it in once to be refurbished, PYI is awesome, the prop came back looking like new and perfectly balanced. Good forward, good reverse, hard to beat............
 

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Closet Powerboater
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Discussion Starter · #20 ·
Sounds like a pretty good consensus that they are awesome. Great news! Even better since the previous owner foots the bill. :)

The greasing issue sounds like the only one I might have a problem with. I've been very lucky with my bottom paint up in our area and typically only haul every 4-5 years or so. Can grease be added while in the water? Can the prop be taken off by a diver like a regular prop in order to grease it?

MedSailor
 
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