Autoprop ?

[sailvi767]

One thing everyone should keep in mind that with a deisel motor it is critically important that the motor will make at least 90 percent of its rated RPM with the props installed under normal conditions. If your engine will not do that you will do damage long term and void most engine warranties. If your engine is rated at 3000 rpm you must be able to attain 2700 minimum with your boat at its normal cruising weight as an example.

[Windgeist]

Originally Posted by fstbttms

Goddam plastic screws on Autoprop zincs! Jeezus, what a poorly designed POS! I hope I never see another one (but I know I will.)

Why don't you tell us how you really feel

I am not sure what plastic screws your talking about on the zinc. There is one stainless nut that holds the zinc on which is over the zerk fitting???

[fstbttms]

Originally Posted by Windgeist

Why don't you tell us how you really feel

I am not sure what plastic screws your talking about on the zinc. There is one stainless nut that holds the zinc on which is over the zerk fitting???

Not on the Autoprop. The manufacturer provides 3 really sh*tty plastic machine screws (called "Anode Retaining Screws") to hold a pyramid-shaped anode to the end of the body of the prop. Worthless POS- see below:



There is an aftermarket adapter that will allow you to install a standard U.S.-style prop zinc. The fact that such a product even exisits is indicative of the crappy design of the Autoprop:



Autoprop Adaptor page

[Alan Wheeler]

I would have thought it a better idea to use the same material the prop is made from. Plastic, hmmmm.

[hellosailor]

Wheels-
I'm guessing that matching the exact alloy the prop is made from, could either be difficult or expensive--since screws aren't offered "stock" in many yellow alloys. OTOH with the great big gob of anode sitting there, any "reasonable" screw might be so thoroughly protected that it would suffice, including common stainless or galvanized varieties. Galvanize might actually have a dual advantage, being zinc jacketed, and having a rougher surface finish which helps it "stay stuck" better than stainless. (I only learned recently that stainless can sometimes be "too smooth" and require thread lock--where galvanized will simply stick from the higher friction.)

But I've got nothing against a properly chosen plastic. DuPont and GE and Phillips all have what they call "engineered plastic resins" and some of them are quote impressive--and expensive. Many of them compete with and exceed specs for metal parts, the only question is "Which plastic and was it properly chosen?"

[Alan Wheeler]

I was thinking and refering to the prop manufacturers fitting the screws. They could easily machine scres made from the same material. Not particularly hard.
Galv coating doesn't work. The very thin surface of the Galv errodes away at the same rate as the rest of the Zinc. Bing so thin, it is not long before it is plain steel. Been there, done that, said Duh!
I don't thinK I would use SST when it is the only SST in a Bronze environment. The anode may protect, but the way I see it is, you only want to protect what you have to. Every additional Reactive combination you create, only serves to make the anode eat away faster. You want to have the anode last as long as you can, (in the restraints of correct voltage protection)

[Windgeist]

Originally Posted by fstbttms

Not on the Autoprop. The manufacturer provides 3 really sh*tty plastic machine screws (called "Anode Retaining Screws") to hold a pyramid-shaped anode to the end of the body of the prop. Worthless POS-

Yup...I am a idiot! We do not have a Auto Prop, its a Auto Stream like this one. Explains what I was thinking...



Google Image Result for http://www.westbynorth.com/images/_autostream.jpg

[fstbttms]

Originally Posted by Windgeist

Yup...I am a idiot!

There are so many different manufacturers of props and so many different brand names (in some cases, several marketed by a single manufacturer) that confusion is bound to happen. I can't keep 'em straight either.

[hellosailor]

"They could easily machine scres made from the same material. Not particularly hard."
Wheels, you're right. And Westerbleake could easily put the hoses and belts on AFTER they paint the whole engine.

That doesn't mean it is going to happen. Some accountant probably said "Well, you'd need a lathe, and a parts bin, and that could take up thirty square feet of floor space, and then you'd need an operator, and rod stock...And it could cost you seventy grand a year. So if you use these here cheap screws and just order 'em by the thousand, you can save enough money to send your kids to college. Or buy that new BMW!"

Gotta get with the program, Wheels. [sigh]

[fstbttms]

Here's my other big gripe about Autoprop; look at the illustration. The only thing holding the prop nut on (and therefore the prop) is a tiny little set-screw. In a perfect world, the set-screw seats on one of the flat faces on the hex-head of the prop nut. But in reality this is sometimes not the case. In reality, the set-screw sometimes seats on the round, barrel body of the nut. In which case the installer must determine where this location will be on the nut and file or grind a flat spot on the body of the nut for the set-screw to seat on. Hopefully when the nut is re-installed, the flat spot on the now modified prop nut will be directly under the set-screw. This, of course, is a pretty much a crap shoot with no fail-safe way to tell if you hit the mark properly or not.





This scenario happens frequently enough that it is addressed by the manufacturer in the installation instructions.

[Alan Wheeler]

I reckon that could be easily solved. By the manufacturer that is. I reckon a small backing plate that has a the hex hole to suit the nut could be easily fitted between the hub and the anode. This could have a series of bolt holes all the way around that would then mean you could tension the bronze nut till it lined up with a hole set and in go the three machine screws...that would be bronze also by the way.

[Eleven]

Thanks for the comments on Broadblue with Brunton's.
I was worried about the props not being up to it but it seems the installed power may be a problem.
Mahe 36's take note that two ten HP's may not /will not drag you off a lee shore. Put it on your shakedown list. We had sea room, thanks to chance and the lord Neptune (who has more control of things than we do).

[Yachts66]

WOW this has been a great thread....but I find myself just about as confused now as I was in the beginning! My refit will begin shortly and re-power and I'm still not sure which prop to go with. I was pretty high on Autoprops until this thread, but the Maxprop seems to have its own set of problems! What's a fella to do?

Regards,

TJ

[dkall]

When I was thinking I would have to return the Autoprop, my next choice was the Luke Feathing prop. Also if I had less than a 50 hp engine there is a prop with plastic blades that is getting a rather high following.

Fair Winds

[RaptorDance]

Yachts66 - it all boils down to where you're planning to go and what you're planning to do.

In spite of some of the negative opinions of Autoprops in this thread. We love ours. Most of the opinions expressed don't translate to actual experiences by the Autoprop owners we've met cruising.

The plastic zinc screws aren't a problem because they only hold on the zinc and you get new ones with every zinc. The flat back of the zinc makes fine electrical contact with the prop.

The set screw on the prop nut isn't a problem since the prop shaft and prop are keyed, the prop always goes back on in the same place. Also, I haven't heard of any one losing the prop because the nut backed off (unlike most fixed props that are held on by just two nuts in series). I've heard of folks losing regular props, Max Props and others, but not the Autoprop.

What has been a problem is folks losing a blade. In every case I've examined, that's traceable back to a lack of maintenance, or improper rebuilding of the prop. Each blade is held on by two nuts, one big one that does the work and a second locking star nut that's reverse threaded. You then must bend over a tab on the star nut to lock with the big nut underneath.

The folks who lost blades didn't think they locked the two nuts together or just plain didn't maintain their prop (you're supposed to grease it at every haul out).

The other problems reported with a loss of thrust when pounding into head seas is a problem with all props. I notice little difference between our Autoprop and other props. Note, it would be better in such cases to have a great big fixed prop with large blade area, any other sailing prop will likely exhibit similar results to what we've seen with our Autoprop.

One other performance killer is growth on the prop. The Autoprop uses hydrodynamics to pitch properly. A bunch of barnacles on the prop can really mess things up. We anchored in Zihuatanejo last year our prop got so dirty we could only do 3 knots instead of our usual 7.5. We had to pull into Isla Grande anchorage to clean our bottom (it got real bad in only a week! Zihua bay is very nutrient rich - which is why I wouldn't dive on it before we left).

So keep it clean, maintain it and you should be happy with an Autoprop, like most of the other owners I know.

Note - I have no interest at all in any way with Autoprop, other than as an owner.

I do have a backup fixed prop, with nuts and a puller just in case. I figure I have that no matter what prop I normally use... However, I've so far, never needed it!

Regards,
Bill