Feathering Prop Choices / Manufacturers

[sailorboy1]

Getting a new boat and want to replace the fixed prop with a feathering prop.

There are a numerous choices as to makes and all of course have some story they try to push. Anyone install one recently and go though the various choices as to benefits of each (far as I'm concerned they all are basically the same far as operation) and price. Are all manaufacturers about the same price since they have to price compete with each other?

Is there a value winner in the choices? (value that's funny considering the prices).

[swagman]

Hi Don,
Afraid I can't comment on US prices but in terms of performance, I understand they do differ.
FWIW we had a Maxprop 3 bladed feathering prop on a 42' Grand Soleil. It was brilliant, much much better than the folding 3 blade on the next 46' Hanse.
You might also check out the newer KiwiProps. We had a pal with a 37 footer took one and found it outperformed his folding prop both in its action and the power it delivered both ahead and astern - but he had the biggest they made and I'm not sure it would be big enough for a 39....
Good luck.
JOHN

[djmarchand]

I have had three different brands: MaxProp, Variprop and Autostream on my boats over the years and I like the MaxProp best. It has wide, fat blades (high DAR) and as a result is less likely to cavitate.

Get the one that allows pitch adjustments without removal. And ask other owners of your boat what size and pitch to use. This is often better advice than the manufacturers.

David

[Hannah on 'Rita T']

We just went through the debate. We opted for the Varifold because we would have had to enlarge the opening and cut our shaft to install a Max prop. Your boat may make your decision for you.

[sailorboy1]

The shaft/prop arrangement on my new boat will take any properly sized prop (lots of room). My current boat has a 3 blade Max Prop. The performance has been fine but that doesn't mean I'm in love with the brand.

[SailFastTri]

Been very happy with 3-blade Volvo-Penta folding props. Not so happy with a 2-blade Varifold. Very unhappy with a Gori 2-blade. Unless things have changed recently you will find Volvo-Penta folding props are much less expensive than the others. Figure about ~$1200-1800 for a three-blade including hub, depending on size.

[night0wl]

Our Beneteau 343 has the Kiwi Prop and so far (after 1 year) I love it! First of all, it was only $1300 or so plus installation (which we got for free because the dealer was doing a lot of work on the boat out of the water already).

Here is where we have benefited:

1) Much better performance under sail...we can actually sail in sub 8 knot winds. With the old 3 blade fixed, we just couldn't get much movement because we were towing a big bucket
2) Better manners under reverse. With the old 3 blade, reversing was a circus. It would go from not catching for what seemed like minutes (as we drifted into danger) to suddenly catching and shooting the stern to port with prop walk and the bow to starboard. Now, its a gentle momentary drift to port and then it catches firm.
3) Hidden benefit...I have better galvanic protection. With the stock Beneteau fixed prop, the zinc went on the prop nut. It was a tiny little cone zinc that I was lucky to get maybe 8 weeks out of since it was right in the way of the prop turbulence and would wear down very quickly. Very poor design Now, with the Kiwi, I use a much larger collar zinc right on the prop shaft itself...and I'm getting much better wear out of the zinc as well since its no longer being shorn off by the prop turbulence. True, I could have used a collar zinc before as well, but it just didn't feet with enough clearance to get water flow to the shaft seal.
4) I haven't used this feature yet, but I may have to in the future. The prop is designed to "lose blades" in case of impact. Much like the design of a IndY Race Car, in case of impact, propeller arms will shear right off, dissipating the energy of impact and saving the hub and hopefully the shaft. Replacement prop arms are $110 each and can be bolted on with an allen wrench.
5) Prop pitch can be adjusted by yourself with a 4mm allen wrench. Mine was tuned too weakly, so I pitched it a bit to get back some of my performance under motor

In terms of negatives:
1) The feathering prop does free wheel while under sail since Yanmar now recommends keeping the transmission in neutral while sailing. It has an audible low frequency hum that could be mitigated with a shaft lock...thats extra expense. I've heard some feathering props autolock

2) I've lost 3/4 - 1 knot in performance under power...especially prevalent in situations when I'm fighting the river current doing bridge work to get home. 2800 RPM used to be 6-6.5 knots with the fixed prop...now 5.5-5.7 knots if I'm lucky. Part of this may be that the prop isn't pitched just right yet, but I'm hesitant to take it TOO far off spec thats recommended for my boat.

3) It needs to be lubed/greased at every haulout. I haven't had my first haulout since putting in the prop yet, but I'm not looking forward to this task

All in all, one of the BEST upgrades I've had done to our boat was adding the Kiwi Prop.

[wilsodf]

We went through the same thing last year when we brought our new Beneteau 37. We went with the Maxprop mainly because of all the good reviews and recommendations from forums like this one. Our boat had a 25 mm shaft and we could only go with the classic three blade. Maxprop did not offer the Maxprop VP with the adjustable pitch without disassembly in our shaft size. The guys at PYI and the Prop Shop in Seattle were a huge help. We brought ours from the Prop Shop in Seattle and they gave us a great deal and helped us over the phone many times during the install.

New Propellers from Prop Shop Propeller Sales & Repairs

Our original prop was a 17 x 12 and we set ours up using their suggested table which we used a 17 x 11.6 setting or a 17" x 20 degree in their table. Our Yanmar 3YM30 has a max RPM of 3600 and we nailed on the first try. As far as pitch adjustment, once you get it right, there is really no need to change it. But if I hadn't, the VP model would have saved a haulout. PYI says they have divers they can refer you to that can change a Classic Maxprop's pitch underwater without a haul-out.

The prop has nice power in reverse and our forward speed seems to be the same as our fixed, maybe slightly less. It feathers with no effort.



Good luck in your search

[fstbttms]

Originally Posted by wilsodf

PYI says they have divers they can refer you to that can change a Classic Maxprop's pitch underwater without a haul-out.

I know this to be true because I am one of them. There is no need to haul a boat to change any Max Prop's pitch, regardless of which model you own. In addition, the is no need to haul a boat to install (or remove) any prop, be it fixed, feathering or folding.

[downunder]

Don't discount the Aussie Seahawk - autostream and slipstream props

Low-Drag, Feathering & Folding Propellers for Sailing Yachts & Sailboats from Seahawk

[Jim Cate]

Originally Posted by downunder

Don't discount the Aussie Seahawk - autostream and slipstream props

Low-Drag, Feathering & Folding Propellers for Sailing Yachts & Sailboats from Seahawk

G'Day all,

Have to agree -- we had an Autostream 3-blade feathering prop on Insatiable I for 10 years and around 60,000 cruising miles. No problems, easy to adjust pitch (both fwd & rev) in the water, free-diving. At time of purchase, cost was about half of Max-Prop.

Do be aware, though, that ALL feathering props share the difficulty of being less efficient than either fixed or folding props. This is due to the requirement that their blades NOT have any twist in them in order to make the feathering work. The lack of twist means a less efficient conversion of shaft horsepower into thrust, and this in turn means poorer fuel economy. In our case, changing from a good two blade folder to the Autostream cost us 25% in fuel usage. The improved thrust in reverse and greater static thrust in forward seemed worthwhile at the time. For our Insatiable II we chose a three blade folder from Flex-O-Fold, and are very happy with it.

Your choice, Mate!

Cheers,

Jim and Ann s/v Insatiable II lying Treharn Cove, NSW, Oz

[sailorboy1]

Thanks for the responses. In looking at various manufacturers websites some claim better power and speed that fixed props (1 I think even better than folding), and at least claims a 30% efficiency improvement. All of course claim better reverse. Difference between 2 and 3 blade units seems to vary from make to make as to pros/cons. Some have simple quote request forms and some complex, and some don't even have a form on-line. For the most oart I would say information on all of their sites is kind of crappy.

Guess I'm going to get a quote from all of them and then compare design afterwards based on that.

[lancelot9898]

I've had my max prop for 25 years now and it's still going strong. From day one when I first bought the boat, I replaced the fix prop with the 3 bladed max prop so no real comparison with performance. I did have to set the pitch up higher than the 17x11 fixed prop due to the reduction in efficiencey of the blade. I think I'm around 13.5 inch pitch. The other things that I remember doing is grinding out the rudder slightly to allow room for the blades to rotate and the shaft was taken to a machine shop to accomodate the prop. I haul the boat out every 3 years and at that time I repack the prop with grease and have played with the pitch some. I could put in a grease fitting so that I would not have to disassemble, but now that I'm use to it I continue thinking that I can clean out the old grease better with it disassembled. If you do disassemble it on the hard I find that an extra set of hands will help. The diver that can do this under water is to be commended since it's hard enough for me on the hard much less in the water with my scube gear on. I also think max prop has a model where you can adjust the pitch without disassembly and that may be very useful to get the proper engine performance, which is another topic where I'm in the minority. Besides the feathering feature of the prop, the reverse if very good and that alone makes the prop for me worthwhile.

[Captain Bill]

We have autostreams on our cat. Jim Cate is corrct about the efficiency. Other people with the same boat and same engines as ours seem to cruise about a knot faster than our boat at the same RPM. The original specs for our boat say it cruised at 8 knots, but ours is closer to 7. Maintenance on the autostreams is pretty simple when out of the water. greasing them once a year in the water seems to be adequate. Though 8 years old there is no sign of corrosion on any of the parts. The biggest problem on saildrive versions is changing the zincs. You have to take the props off to do so and that is a pain. One has to disassemble the prop to remove it and that is difficult to do in the water. The clearance of the hub against the saildrive is too small to use the 2 piece quick change zincs available for Yanmar saildrives. Fortunately for us our zincs last quite a long time. Pitch adjustments are easy in the water or out. Reverse thrust is superior to folding or fixed props. Fuel burn is about 3/4 of a gallon per hour per engine. which is in line with the specs for the engine at cruise speed, so we pay the penalty on speed. If we tried to run at 8 knots we would pay a huge fuel penalty as we achieve 8 knots at only maximum continious power at which we burn about 2.5 gallons per hour per engine. I've tried not feathering the props while sailing just to see what it costs us in speed and that amounts to about 1 to 1.5 knots whith the penalty increaing as speed goes up.

[denverd0n]

From the Aussie company mentioned above, which sells all types of propellers, a good comparison of the pros and cons of fixed, folding, and feathering...

Seahawk: Feathering, Folding or Fixed Propeller?