Autoprop??

[Yachts66]

There has been some discussion here about Maxiprops, but sparse little has been said about the autoprop. The concept really appeals to me, but it's always good to hear from the folks who are actually using them....so.....what do you autoprop users think about this product?

Much thanks,


TJ

[Talbot]

They have a good reputation in europe. - autoprop

There is also the Gori:

[Ed Steele]

My boat came with an Autoprop and I have used it for 17,000 miles over the past three years. What to say about it? Well it works fine. I haven’t taken it off to compare with another brand or with a fixed prop. For maintenance, I grease it every time the boat is lifted and make sure it is kept free of barnacles. The only problem I have had has been with the prop-shaft brake – leaking seals, worn brake shoes etc. My transmission is hydraulic and needs to be “braked” when the engine is not running so that the prop will fold. I don’t “know” but I expect that a similar arrangement of brake with its attendant complexity would be needed for any folding prop when using a hydraulic transmission.

[S/V Elusive]

While I've seen the Autoprop at the boat show, I couldn't figure out if there was any benefit over the maxiprop (new ones).

The one I have works VERY well for me; with the exception of being able to change the pitch without hauling out. The new ones can do that.

As for shaft turning, with the Maxiprop, it is very simple; when you turn off your engine, leave it in forward. The prop turns until it is feathered and stays there.

One other item, with the maxiprop - the prop nut zincs are readily available all over the US. Don't know about the Autoprop.

[Moby Dick]

From all that I have seen and heard, the Autoprop maximises engine efficiency, compared to other folders/featherers that may maximise sailing performance.

The Autoprop self-pitches - so you can e.g. motor sail with minimum revs, or push into head seas where your speed drops but the Autoprop compensates by adjusting pitch to give maximum push.

The result is, you might get away with a smaller engine, or you get better performance when going into weather.

Downside is 1) cost 2) more drag than folders when sailing

[Jeff H]

There has been a lot of discussion about the relative merit of Autoprops vs more conventional feathering props. I have seen very little criticism of feathering props like Maxiprop or Luke Feathering propellers. Autoprops have a pretty big following but I have seem a number of disgruntled owners who have reported a variety of disappointments. One thing that seems to come through from many of the treads with disgruntled autoprop owners that I have read is that that Autoprops claims of increased efficiency do not seem to hold up in actual practice, and they don't seem to work as well as folks would like in a seaway.

Gori makes a nice looking propeller (I had nearly half a dozen on one of my boats as one after the other failed). I actually don't fault them for the fact that their props were failing (it was a design defect that I think other sialdrive props had as well and which I think they ultimately cured) but I found their service in North America and their attitude toward standing behind thier product to be absolutely dismal. Unless I lived within driving distance of the factory, I personally would not buy another boat with a Gori, no less replace a propeller with one.

Jeff

[Moby Dick]

".....they don't seem to work as well as folks would like in a seaway"

- Any reference to such comments? I have not tried them in a seaway yet, but they DO make a difference when motor sailing (as they re-pitch for the different speed/thrust requirements).

[rickm505]

This is the MIT study of ten sailboat propellers, Autoprop and Maxiprop included.

It's good reading

http://thepracticalsailor.com/Files/.../propeller.pdf

Rick in Florida

[Jentine]

This and other studies show autoprop to be less than claimed. For the price, it should be the best available.

http://www.cruisingsolutions.com/prop.htm

[Moby Dick]

Hmm - reports quoted by a company that sells a competing solution. Excuse my large pinch of salt.

[Weyalan]

Originally Posted by rickm505

This is the MIT study of ten sailboat propellers, Autoprop and Maxiprop included.

It's good reading

http://thepracticalsailor.com/Files/.../propeller.pdf

Rick in Florida

Interesting reading indeed. Unfortunately, the report seemed, to me at least, to become a little bit over-complex, to the point of obfuscation.

For me, a graph of thrust coefficent and torque coefficient against advance coefficient did not really tell me anything meaningful. J, Kt and Kq just do not mean much. It appeared to me that figures 2 through 11 really only compare each prop to itself, and is therefore of only limited usefulness (although I admit that my understanding of the math is not great). I would liked to have seen a simple graph showing the thrust generated against rpm.

The graphs that were most illuminating for me were:
Figure 13: This graph showed a direct comparison of each prop in terms of (reverse) thrust generated at a given rpm. Why they could not have given a similar graph comparing forward thrust beats the heck outta me!
Figure 14: This graph showed a direct comparison of drag generated at a given water velocity (i.e. boat speed).

I shall now go and re-read the whole thing to see if I can make any more sense of the bits that seemed overly boffinish at first read.

[rickm505]

I agree, It could have been written clearer, but since when has MIT ever taken a simple approach?

In any case, it's unbiased.

Rick in Florida

[dkall]

http://cs-bb.com/forums/csbbarchives...30856,Autoprop

We choose the Autoprop mostly after two years of reading everything I cold I like that 1) I don't have to modify my shaft and can carry a cheapO spare fixed prop, 2) I had read that overtime the Maxi prop will wear the stops and 3) I like that it is self adjusting for what ever load sea state there is.

As we've not yet lauched I can't really say how it goes. Auto prop shows on their site some stop test with moving boats that looks favorable. Of course it is on their site. But I do like the idea of a dynamic test opposed to a static test of what a prop on various boats will do.

[dkall]

I'm currently dealing w/ Autoprop in a new install. I followed the manufacture - distributers rep suggestions and have the following.

Hull speed is reached at 1300 rpms when the engine max is 2600. At 1400 rpms I receive a HUGE vibration with bending of the shaft.

The prop stops the boat very quickly. Almost on a dime if one can say that about stopping boats.

I have an enclosed area for the prop (full keel boat) and rudder.

I checked w/ Autoprop the diagrams they sent and sized the prop accordingly. The diagrams they sent with the correct prop showed that it fit the opening.

I know of two sisterships boats with Autoprops that don't have this issue so I'm hoping to get this resolved soon.

I liked the Autoprop because at the time I couldn't find any negative comments about them. I like them because there is no mechanical stop. I like them because the auto pitch to current conditions. I like them because I didn't have to modify the end of the prop for any nuts and can in an emergency put a fixed prop back on.

I don't like the vibration issue but hope to get that resolved soon.

I do feel they overproped me. I have an 1/14" shaft and the prop they said was best was 21". I believe that is above the ABYC recommended standard.

I believe the issue will be resolved soon and I'll be entirely satisfied with the setup.

[Moby Dick]

is that a two blade or three blade Autoprop?