Autoprop ?

[neelie]

Thanks for the great review, Dockhead

Ecowind?? First I've even heard of this one and it promises the same performance increases as the Autoprop delivers.

I've just tried searching for reviews and opinions on the Ecowind, despite being on the market for 2 years now, there seems to be only one or two who have commented on it with first hand experience. Hey ho.. more Googling required.

[Dockhead]

By the way:

One thing very much worth doing for all propellers which have moving parts, is to send them back to the manufacturer for inspection on a regular basis.

I sent mine to Brunton's a few weeks ago. They took it apart, cleaned it, replaced all the bearings and seals, checked everything for wear, recut the blades where there were nicks, then rebalanced the whole thing. Fitted a new anode. All this for 290 pounds, or less than $500. So now it's good as new again and I don't need to worry about the bearings etc.

My father has a Brunton prop (the old kind with the water lubricated bearings) and he doesn't bother. It's been in the water continuously for 15 years and he never does anything but change the anodes sporadically (by diving; he almost never hauls his boat). Has worked perfectly for 15 years and thousands of hours.

But a mission-critical part like this, which is also a safety-critical part, with moving and wearing components, should be regularly serviced IMHO.

[Dockhead]

Originally Posted by neelie

Thanks for the great review, Dockhead

Ecowind?? First I've even heard of this one and it promises the same performance increases as the Autoprop delivers.

I've just tried searching for reviews and opinions on the Ecowind, despite being on the market for 2 years now, there seems to be only one or two who have commented on it with first hand experience. Hey ho.. more Googling required.

The Ecowind looks very cool. I'm also looking forward to hearing more about people's real experiences, but I've never known anyone who fitted one.

[hellosailor]

Mission-critical? Well, that's only the auxiliary engine, so perhaps not.

But if it were mission critical and you planned to send it home for re-education every year, you do have a spare prop of some kind aboard, yes?

[chala]

Originally Posted by Dockhead

All this for 290 pounds, or less than $500.

Lucky you. Now add the freight from and to the other side of the world? With all the good words from you, they must have given you a special price.

Originally Posted by Dockhead

My father has a Brunton prop (the old kind with the water lubricated bearings) and he doesn't bother. It's been in the water continuously for 15 years and he never does anything but change the anodes sporadically (by diving; he almost never hauls his boat). Has worked perfectly for 15 years and thousands of hours.

Could you elaborate on the difference between the old kind and the new kind? It makes you wonder why a new kind is necessary if the old one is that reliable?

[Talbot]

My autoprops are 6 years old.
They have a central rubber bush to absorb shock loading. The life span is aproximatly 6 years. The hub design has now been changed to allow a different design of rubber bush. The old bush can fail and leave you with no drive. When the new design fails it still leaves you with partial drive as the rubber tends to lock up inside the hub. The new rubber bearing are a series of pencilled shaped rubber sections placed length ways. You can update your hubs and bearings but it is not cheap.

And I have two of them!

[chala]

Originally Posted by Talbot

My autoprops are 6 years old.
They have a central rubber bush to absorb shock loading.

And I have two of them!

You must have a saildrive. There are no rubber bushes on a H5.

[Talbot]

Originally Posted by chala

You must have a saildrive. There are no rubber bushes on a H5.

Yes. two of them.

[fstbttms]

Originally Posted by chala

It makes you wonder why a new kind is necessary if the old one is that reliable?

The old one aren't that reliable. That's why Brunton's had to redesign them.

[Dockhead]

Originally Posted by chala

Could you elaborate on the difference between the old kind and the new kind? It makes you wonder why a new kind is necessary if the old one is that reliable?

Old kind had water-lubricated bearings. New kind you have to grease every time you haul out.

FastBottoms is confused about the design evolution of Bruntons. There was a run of props with bad locking washers which allowed a nut to back off and so a blade to be thrown. There was a recall for this. There is nothing wrong in principle with water lubricated bearings -- your cutless bearing is water lubricated, and it carries vastly more stress than the blade bearings of an Autoprop, which don't spin around continuously like a cutless bearing, but just turn a little to allow the blades to feather.

All good engineered products evolve with time, experience, etc. Would you ask -- "What was so wrong with the DC3, that they had to go an design the 707?" Or "What was so wrong with the E39 BMW, that they had to come up with the E60? Makes you wonder . . . " A really strange question, IMHO.

There are plenty of good props, for anyone who doesn't like, for any reason, the Autoprop. Bruntons don't even have a monopoly on self-pitching props since Maxprop came out with the Ecowind, which I bet is a really great prop. The biggest drawback of Autoprops is that they droop a blade when they are feathered, creating the highest drag when feathered of any feathering or folding prop. This the tradeoff for the ingenious simplicity which allows Autoprops to be made without any springs or gears at all. This tradeoff makes it a poor choice for racers, or for catamarans, probably. If the Ecowind doesn't suffer from this (and it has springs, so I bet it doesn't) I would consider switching myself, although on my particular boat, it is not all that noticeable.

[Dockhead]

Originally Posted by hellosailor

Mission-critical? Well, that's only the auxiliary engine, so perhaps not.

But if it were mission critical and you planned to send it home for re-education every year, you do have a spare prop of some kind aboard, yes?

My first two sailboats had no engines of any kind, so sailing onto and off a dock or a mooring is not an unfamiliar experience for me. Nevertheless, I would never want to be without engine power on my present boat, which weighs 25 tons. Losing mechanical propulsion would be a serious situation, like for many cruisers, and I would not put out to sea without working mechanical propulsion. The idea of "auxiliary" propulsion is a bit outdated, I think.

Therefore, of course I carry a spare prop, as everyone should who has feathering or folding props with moving -- read, breakable -- parts. I was sailing in the Windward Islands some years ago when my chartered catamaran threw the blade of one of its Flexofold props. Any feathering or folding prop can break.

I don't send my prop off for service every year. It would be pretty hard since I sail year round and don't usually haul out for more than an hour at a time. Every three to five years is enough. If you have a Maxprop, or Varifold, or other prop with moving -- read, breakable -- parts, I highly recommend the same regime.

[fstbttms]

Originally Posted by Dockhead

FastBottoms is confused about the design evolution of Bruntons. There was a run of props with bad locking washers which allowed a nut to back off and so a blade to be thrown. There was a recall for this. There is nothing wrong in principle with water lubricated bearings -- your cutless bearing is water lubricated, and it carries vastly more stress than the blade bearings of an Autoprop, which don't spin around continuously like a cutless bearing, but just turn a little to allow the blades to feather.

No, FastBottoms is not confused about the design evolution of this prop and is here to tell you that the water-lubricated bearings in the Autoprop have nothing in common with water-lubricated cutless bearings, other than the fact that they are water lubricated. Cutless bearings have a close enough tolerance that fouling organisms cannot enter. The same cannot be said for the ridiculously wide-open bearing races on the Autoprop. And if you'd ever had to brace your feet on the underside of a boat and attempt to force a fouled Autoprop blade into motion, you'd understand what I'm talking about.

[chala]

Originally Posted by Dockhead

There is nothing wrong in principle with water lubricated bearings -- your cutless bearing is water lubricated, and it carries vastly more stress than the blade bearings of an Autoprop, which don't spin around continuously like a cutless bearing, but just turn a little to allow the blades to feather.

I do not see it that way. The stress on a cutless bearing are small and mainly due to gravity (weight of the shaft, prop and accessory (shaft zinc, rope cutter, etc)), prop walk (lateral force), water turbulences. The main force of propelling forward or backward is taken by the engine, gearbox or a trust drive (aquadrive, etc) and their respective mounts and the prop. In a moveable blades prop configuration the main force of propelling forward or backward must also be carried by the blades bearings. In an Autoprop, the design must allow for the blades to turn freely under full load. For this to be achieved, it looks like that the designer decided to shoulder the Taper Roller Bearings (6) with a Thrust Race Bearing (9). It is possible that the use of grease is there to help prevent corrosion of the many parts of the prop, my guess. As for “continuous spin versus a little turn” see False brinelling - Wikipedia, the free encyclopedia

[carstenb]

I'll let you guys know how I like the Ecowind. I'm mounting one later this spring

[Shamancat]

Hi I have autoprops on a SD50 drive on my cat. Recently one failed after less than 400 hours leaving that engine with no drive - the rubber insert failed. About a thousand dollars to repair from Brunton and they refused to answer any questions about the failure. Plus haulout, shipping and 6 weeks lost. Also the zinc anodes can fail quickly if the thin area around the screws dissolves. I am happy with the performance but my pal is a dealer for many props and says the Max props are much more reliable but not easy to get the pitch right. If another one fails I am taking them off and switching. Very disappointed....