New Prop Opinions - folding/feathering

[Letterkenny]

Originally Posted by s/v Jedi

Please provide citations for your “fact” of 30% less fuel used. Facts are always documented; without supporting documentation it’s just personal opinion.

Edit: same for reverse thrust. All I can find shows that Maxprop has much more reverse thrust than any other prop.

Have you noticed or otherwise seen an increase in cruise speed with the maxprop?

[maine50]

I just replaced a 3 blade feathering with a 3 blade folder (flexofold). Couldn't be happier- much better motoring into waves and better speed at same RPM. Also much cheaper than a max prop and I think less maintenance. The flexofold is very substantially built and with the gears all the blades open quietly. I'm driving this with a Beta Marine 38hp on 24k boat. Reverse is not as good as the feathering prop (kiwi prop) but not a concern as the forward thrust is so much better as shown by my experience and those test results indicated above.

[Letterkenny]

Originally Posted by maine50

I just replaced a 3 blade feathering with a 3 blade folder (flexofold). Couldn't be happier- much better motoring into waves and better speed at same RPM. Also much cheaper than a max prop and I think less maintenance. The flexofold is very substantially built and with the gears all the blades open quietly. I'm driving this with a Beta Marine 38hp on 24k boat. Reverse is not as good as the feathering prop (kiwi prop) but not a concern as the forward thrust is so much better as shown by my experience and those test results indicated above.

Haven’t received my flexofold quote yet but currently the maxprop is the most ($3,500) then the Autoprop ($3,100 at current FX rates).

Edit: for those with a maxprop or Autoprop, can the annual greasing be done in the water or do I have to haul every year?

[maine50]

I got a slightly better price by going thru a dealer in US- I think the price was about $2200 3 month ago.

[CarlF]

I looked at the Autoprop but was told by several that its drag under sail was significantly larger than the competition. I much prefer to sail than motorsail.

My concern with the maxprop is a) flat inefficient blades, b) annual maintenance, c) blades sticking out sailing are more prone to catching lobster pots

My last boat had a Flexofold - liked it a lot. Very powerful in forward, pretty weak in reverse but on a monohull reverse isn’t that important. Only maintenance was changing zincs.

New cat has Gori three blade. More expensive than Flexofold but much stronger in reverse (which is important on a cat when maneuvering in a marina as no bow thruster) Similar performance to Flexofold in forward. Has an “Overdrive mode” that gives you about 2” additional pitch. Can run engine 500 rpm slower with similar hull speed but fuel use is about the same (heavier loaded engine) Should have bushings replaced every three years. Otherwise only maintenance are zincs.

[s/v Jedi]

Originally Posted by Letterkenny

Have you noticed or otherwise seen an increase in cruise speed with the maxprop?

Originally Posted by Letterkenny

Haven’t received my flexofold quote yet but currently the maxprop is the most ($3,500) then the Autoprop ($3,100 at current FX rates).

Edit: for those with a maxprop or Autoprop, can the annual greasing be done in the water or do I have to haul every year?

I think cruise speed as well as hull speed are determined by the length of the waterline, not by the type of prop.

When one prop is more efficient than the other, you reach your “cruise speed” at a lower fuel consumption than the other prop, but that speed doesn’t change.

Also, RPM is determined by the gearbox and the size of the prop. With MaxProp you can change the pitch to change RPM for cruise speed.

We do grease out Maxprop in the water. We remove a little socket screw, screw the grease nipple in, pump the grease gun until clean grease comes out the blade attachments, then clean and pack up.

The grease gun must be rinsed with fresh water, then sprayed down with wd40, then we wrap it in a cloth that is heavily sprayed with wd40, then into a ziplock. We use the small size grease guns to make this easier.

[Jim Cate]

New cat has Gori three blade. More expensive than Flexofold but much stronger in reverse (which is important on a cat when maneuvering in a marina as no bow thruster) Similar performance to Flexofold in forward.

This observation is quite contrary to the data presented in the above quoted YW test, where the FOF outperformed the Gori in every category measured.

Perhaps your experience was due to other factors than the change in props?

Jim

[fstbttms]

Originally Posted by Letterkenny

…for those with a maxprop or Autoprop, can the annual greasing be done in the water or do I have to haul every year?

There is almost no reason to ever haul a boat to repair or maintain ANY prop, Max Prop included. In-water lubrication is a 15-minute job.

https://youtu.be/EiGowIK-GGI

[Searles]

Check out kiwi prop ,many pluses ,fitted many ,much cheaper than others ,simpler to fit ,adjustable under water .⛵️⚓️

[GILow]

Originally Posted by Searles

Check out kiwi prop ,many pluses ,fitted many ,much cheaper than others ,simpler to fit ,adjustable under water .[emoji569]️[emoji572]️

Yep,another vote for the kiwi from me. [emoji106]

[JimsCAL]

Matching the prop pitch to the engine is probably the most important thing in getting the most out of the power plant. Too much or too little pitch and you won't get rated power out of the engine.

I have a 2 blade Martec folder on my Yanmar 3GM30F. If I need to replace it, I will probably go with a 2 blade FlexOFold.

[MicHughV]

Prop performance is kinda hard to pin down as everybody is likely to have an opinion based on his/her experience.

A better way might be to tabulate the differences.

a. Price point.
b. Availability.
c. Service and maintenance required.
d. ease of installation and/or removal.
e. Performance in reverse.
f. Material used.
g. Manufacturer assistance, warranty and assistance.
h. Worldwide availability of spares, etc.
1. strength
j. underwater service availability.

Just to name a few things...

[Jammer]

I have a Maxprop and find it to be a good compromise. Little drag under sail, good reverse performance, sufficient forward performance. If it were to fall off the shaft I would probably replace it with a Flexofold for somewhat better forward performance, somewhat less drag while sailing, less maintenance, and somewhat less of a propensity to catch lines while sailing -- at the cost of poor reverse.

Originally Posted by Letterkenny

Have you noticed or otherwise seen an increase in cruise speed with the maxprop?

No. My boat performs to the performance curve in the book. Hull speed is hull speed.

The very best prop at normal cruising speed is a properly chosen fixed pitch prop. The idea that this can be improved upon is pure bunkum, and any analysis is complicated by the fact that minor changes in pitch can lead to minor changes in performance. If you get a big improvement at cruise out of switching to a feathering prop then the prop you had before was the wrong prop for your boat.

The whole point behind fancy props is that you can sail faster in light winds. With a feathering prop you give up a little forward for this but pick up improved reverse performance. With a folding prop your forward is the same and your reverse is worse.

I have experimented with different fixed props on other boats and am skeptical of Autoprop's claims of improved performance through variable pitch. Small changes in pitch don't make large differences in fuel economy. You can get somewhat lower RPMs and noise but I don't believe there is any way for specific fuel consumption to be notably different.


Bottom line, the folding and feathering props out there are more the same performance wise than they are different: You get way better performance sailing in a light breeze with various other tradeoffs.


Unhappy with performance? Empty all the heavy crap out of the lockers, have the bottom scrubbed, and get an asymmetric.

[Letterkenny]

Originally Posted by Jammer

I have a Maxprop and find it to be a good compromise. Little drag under sail, good reverse performance, sufficient forward performance. If it were to fall off the shaft I would probably replace it with a Flexofold for somewhat better forward performance, somewhat less drag while sailing, less maintenance, and somewhat less of a propensity to catch lines while sailing -- at the cost of poor reverse.



No. My boat performs to the performance curve in the book. Hull speed is hull speed.

The very best prop at normal cruising speed is a properly chosen fixed pitch prop. The idea that this can be improved upon is pure bunkum, and any analysis is complicated by the fact that minor changes in pitch can lead to minor changes in performance. If you get a big improvement at cruise out of switching to a feathering prop then the prop you had before was the wrong prop for your boat.

The whole point behind fancy props is that you can sail faster in light winds. With a feathering prop you give up a little forward for this but pick up improved reverse performance. With a folding prop your forward is the same and your reverse is worse.

I have experimented with different fixed props on other boats and am skeptical of Autoprop's claims of improved performance through variable pitch. Small changes in pitch don't make large differences in fuel economy. You can get somewhat lower RPMs and noise but I don't believe there is any way for specific fuel consumption to be notably different.


Bottom line, the folding and feathering props out there are more the same performance wise than they are different: You get way better performance sailing in a light breeze with various other tradeoffs.


Unhappy with performance? Empty all the heavy crap out of the lockers, have the bottom scrubbed, and get an asymmetric.

More so, I’ve seen people with my same boat have different performances under power. Granted, there are multiple variables but I do believe that the Autoprop may have higher speeds at a given RPM range due to the variable pitch. With my current configuration, my boat can barely hit hull speed flat out. The sail performance will be substantial with any of the options which is why I haven’t been as focused on that. Currently leaning towards the flexofold or the maxprop, though.

[Uncle Bob]

Originally Posted by GILow

Yep,another vote for the kiwi from me. [emoji106]

aaaaaahh so you have decided on a way to continue the use of your kiwi prop.