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**Dockhead** · 03-01-2013, 09:31

Quote:

Originally Posted by hellosailor

Dockhead-
Perhaps part of the answer lies in the same issue that bedevils bottom paint? That is, the nature of the surrounding water. A water-lubricated bearing will also be abraded by whatever is in the water. If the somewhat cold clear waters around the UK contain less abrasive matter, the bearings will hold up just fine, as compared to warmer waters with more life, perhaps full of gritty little diatoms and more particulate matter?
I'm sure someone, somewhere, knows how "local" waters compare that way but I suspect that information would be hard to come by. It would be interesting to find out though.

Could be - I couldn't say. Cutless bearings are water lubricated, too - it's not an uncommon technology.

hellosailor · 03-01-2013, 09:58

Good point. How cutless bearings are different from the bearings in your prop, or whether it is a matter of area, deformation, wear, materials...I guess that's why the good lord made engineers, huh? :-)

k7cej · 03-01-2013, 11:48

My experience with the Autoprop has been very successful. We have an Outbound 44 with a Yanmar 75HP engine. Since launching in 2001 we have crossed the South Pacific, sailed to Mexico and returned via Hawaii, motored to Alaska, circumnavigated Vancouver Is., etc. Sequoia has logged over 30k nm, maybe one-quarter of that under power, without prop problems.

I will say that when we ordered the prop in 2001 there was a lot of discussion because the previous fitting to an Outbound has been based on a mistaken engine spec. After the first season for us, Brunton recalled the prop and rebuilt it based on loose blade issues on other boats. (They paid for the haulout and shipping, pretty good support.)

Our prop has sealed bearings, a systems which appears to work as advertised. The custom zinc is pricey, and the three 1/4" nylon bolts attaching the zinc always look marginal, but I have never had one break or come adrift. The prop really shines at extreme conditions: motor-sailing with low revs (like when battery charging on passage) or forcing a pass in high winds and heavy seas. I am very pleased with it in all respects.

Some other Outbound owners have Maxprops, which they also find satisfactory. I chose the Autoprop because of its auto-adjusting capability. It increased our speed from 5 to 7 knots in calm conditions at 2000 rpm compared to the old fix-bladed prop, and lots of battery charging at fast idle speeds doesn't seem to have harmed the engine so far. I can't make a direct comparison to the Maxprop, but I suspect that a properly adjusted Maxprop gives comparable performance at its design point, just is not as efficient at the extremes. My 2 cents.

Craig

fstbttms · 03-01-2013, 21:19

Quote:

Originally Posted by Dockhead

I am not sure that the sample of thrown blades is statistically significant. Do we know that the old Autoprops did that any more than any other folding/feathering prop?

I have personally seen 2 or 3 Autoprops that have thrown blades. That is a relatively large percentage of the total number of Autoprops that I have serviced. I can't recall ever having seen any other folding or feathering prop lose a blade. And we are talking about thousands of boats that I have serviced in my 18+ years in the business.

I'm not saying that every Autoprop that has ever been installed is a POS. But based on my experience, there are much better designed and more reliable options. And I do not hesitate to tell my clients as much when asked.

**Dockhead** · 03-01-2013, 22:39

Quote:

Originally Posted by fstbttms

I have personally seen 2 or 3 Autoprops that have thrown blades. That is a relatively large percentage of the total number of Autoprops that I have serviced. I can't recall ever having seen any other folding or feathering prop lose a blade. And we are talking about thousands of boats that I have serviced in my 18+ years in the business.

I'm not saying that every Autoprop that has ever been installed is a POS. But based on my experience, there are much better designed and more reliable options. And I do not hesitate to tell my clients as much when asked.

Somehow I don't doubt what you tell your clients

2 or 3 props with thrown blades is a fairly insignificant statistical sample. It's only two to three times the size of my statistical sample of thrown blades with Flexofold props, yet I don't go around bashing Flexofolds, saying something like, what carp they are, 100% of Flexofolds I sailed with threw blades, and I've been around thousands of boats since I started sailing 40 years ago! No prop other than a Flexofold ever threw a blade, ergo, they are carp!

There was a design mistake with the early Autoprops, but it was not water-lubricated bearings, which as far as I know are OK, but with a mis-designed locking washer which allowed blade axle nuts to work free. As someone else mentioned above, there was a recall for this. Probably the props you saw had this problem. It is not reasonable to issue a bombastic, blanket condemnation of the design and construction of these devices based on one, long-corrected production mistake.

fstbttms · 04-01-2013, 05:46

Quote:

Originally Posted by Dockhead

t is not reasonable to issue a bombastic, blanket condemnation of the design and construction of these devices based on one, long-corrected production mistake.

The blade-throwing issue is only one of my gripes about the Autoprop. I'm still trying to wrestle frozen blades into proper movement, still trying not to bust the really crappy plastic anode screws which inevitably seize-up in their holes etc., etc. Recall or not, those early, open-race models are still out there and are still a PITA.

CAELESTIS · 04-01-2013, 06:44

Back to the actual performance of the prop. . .

Has anyone used both the autoprop and the newish Ecowind prop from Maxprop?

Feedback?

neelie · 04-01-2013, 16:38

Quote:

Originally Posted by fstbttms

The blade-throwing issue is only one of my gripes about the Autoprop..

OK, OK, we hear you, we hear you! Your credential are well noted.

This may piss you off, but despite your one man war, I am seriously thinking of installing an Autoprop to increase my motoring range.

So I'd really like to hear from people who have one installed. I am most interested in their experience with respect to increases in range or speed when compared to a regular feathering prop.

fstbttms · 04-01-2013, 16:47

Quote:

Originally Posted by neelie

This may piss you off, but despite your one man war, I am seriously thinking of installing an Autoprop...

Hey, it's your dime. Do what you want, it makes no difference to me. I'm just here to relate my experience with this product. What you call my "one man war" is simply me responding to others quoting my posts.

Yachts66 · 04-01-2013, 19:32

Just some random thoughts and words of caution:
Zinc fumes are toxic!! Be very careful when you melt zinc. Like lead, zinc fumes can make you very ill and even kill you. Granted melting enough zinc to make on anode is probably not going to kill you, but it could make you sick if you're not very careful.

Zinc anodes are usually not pure zinc! They are alloys and the discarded anodes laying around the boat yards have had the alloys sacrificed out of them and are no longer as effective. So, when you melt them down you are not going to have a new zinc that worked as well as the one you bought in the store. Will it work well enough? I can't say, but I can say there is a risk it won't.

neelie · 04-01-2013, 20:20

Quote:

Originally Posted by fstbttms

Hey, it's your dime. Do what you want, it makes no difference to me. I'm just here to relate my experience with this product. What you call my "one man war" is simply me responding to others quoting my posts.

First off.. Your credentials are unquestioned and your opinions are highly valued.

That being said, you do yourself a disservice by simply not letting go of the bone.

Perhaps, my previous post may have seemed like a personal attack to you, I assure you it wasn't intended to be. This is an international forum - we all have different turns of phrase depending on our linguistic roots.

Your points about the Autoprop have been well noted and these are questions I will be asking them before I hand over my hard earned cash or not!

delmarrey · 04-01-2013, 20:52

Quote:

Originally Posted by neelie

First off.. Your credentials are unquestioned and your opinions are highly valued.

That being said, you do yourself a disservice by simply not letting go of the bone.

Perhaps, my previous post may have seemed like a personal attack to you, I assure you it wasn't intended to be. This is an international forum - we all have different turns of phrase depending on our linguistic roots.

Your points about the Autoprop have been well noted and these are questions I will be asking them before I hand over my hard earned cash or not!

I don't like'm either!

You should do the research on the forum here. There are pages upon pages of problems with the things>>>> autoprop - Google Search

fstbttms · 04-01-2013, 20:59

Quote:

Originally Posted by neelie

Perhaps, my previous post may have seemed like a personal attack to you, I assure you it wasn't intended to be. This is an international forum - we all have different turns of phrase depending on our linguistic roots.

I did not take your post to be any kind of attack against me.

**Dockhead** · 07-01-2013, 22:32

Quote:

Originally Posted by neelie

So I'd really like to hear from people who have one installed. I am most interested in their experience with respect to increases in range or speed when compared to a regular feathering prop.

I've had them on two boats over about 13 years of cruising.

What they do in terms of performance is this.

1. They are always ideally pitched, for every particular load or RPM situation. So that means that the overall average fuel burn will be dramatically better -- as in half or less -- than a prop which is not quite pitched right. The gap is less if you really get a regular prop right, but this can be tedious. It's better with something like a Maxprop because the pitch of that can be adjusted easily without a haulout, so it's possible to experiment.

2. You will not be able to motor very slowly. At idle, the Autoprop pitches right up and will keep driving the boat. I think my slowest speed is about 4 knots. It was disconcerting at first, but you get used to pulling back in neutral and giving an occasional burst when needed.

3. Another drawback -- the Autoprop has relatively great drag when sailing with the engine shut down. Due to the design, one blade droops when the prop is feathered. Still 1/10 the drag of a regular prop, but several times more drag than the best of the other feathering or folding. I don't notice it on my boat, but it might be noticeable on a light, high performance boat.

4. It takes a little time for the blades to switch over when you go from forward to reverse or vice versa. Also disconcerting for some people. But once they are over (a long fraction of a second), they bite hard. They thrust in reverse is incredible if you are used to fixed props.

5. The motorsailing is incomparable. It opens up new horizons. You can motor at 1200 rpm with the engine practically inaudible and get a lot of thrust helping out the sails, on a calm day. It really extends the wind range when you can keep the sails up, and greatly increases the pleasure of sailing on a calm day. The prop will change pitch as the sails give more or less drive. The other great thing about this is that the prop will keep the engine loaded up well so that it is not harmful for the engine to motor at such low revs.

6. On really glassy calm days when it takes very little thrust to move the boat, you can cut the revs right down. I crossed the English Channel in a dead calm one time, a beautiful day, with a lot of guests on board. The long way, in the West, more than 100 miles. Everyone was hoping for a fun sail but there was zero point zero knots of find -- a total flat calm, the sea like a mirror. With any other prop the fun would have been spoiled, grinding across at usual cruising revs. But with the Autoprop, it was possible to throttle down to about 1400 RPM where you almost couldn't hear the engine at all, and the boat was still cutting through the water at 7.5 knots. It was magical, and a memorably pleasant crossing. Not possible with any other kind of prop.

7. In tough weather, punching through head seas, the Autoprop shifts down a couple of gears and will make best use of all the power the engine has, to get you through. A fixed pitch prop is like having one gear. The Autoprop is infinitely variable from a granny gear to overdrive.

As to your main question -- as I started to say in 1 above -- the difference in range is dramatic compared to the usual case of a slightly mis-pitched prop. I think my fuel burn fell by about half when I installed the first Autoprop on my first boat, and the old prop was not grossly mispitched (it was the prop the boat was delivered with new). If you spend the time to get the pitch exactly right with something like a Max Prop, the gap narrows, but I reckon you will still gain 20% of range even against the Platonic ideal of a fixed pitch prop, in an ordinary cruising regime, and a lot more than that still if you do any motor sailing. It's the same with speed. I can reach 10 knots under motor in my boat with a clean bottom and flat seas, and I get there right at redline. People I know with the same boat and different props can't even make 9. Keep in mind that the ideal pitch for best speed and the ideal pitch, as is the ideal pitch for best economy. So no matter how much you fiddle with your fixed pitch prop, you will not have everything.