Autoprop ?

[Yachts66]

Well, no actually, you can drill underwater, just use an air powered drill available at any auto parts store and not expensive. If you're in salt water rinse with fresh water well and dry it when the job is finished.

Use a screw extractor, and yes you need to drill a hole in the nylon, but that should not be too hard.

[Tessellate]

Originally Posted by Yachts66

Well, no actually, you can drill underwater, just use an air powered drill available at any auto parts store and not expensive. If you're in salt water rinse with fresh water well and dry it when the job is finished.

Use a screw extractor, and yes you need to drill a hole in the nylon, but that should not be too hard.

Hmm, I hadn't heard of air drills... looks like a cheap air drill is $50 and a cheap air compressor is $100. Not exactly my idea of "not expensive". If I'm going to do a $200 zinc replacement I may as well hire a diver.

It's a lot harder to work underwater than people here seem to think. It's not like solid ground where I can use legs and body weight to apply pressure to the bolt. All while my body is floating up because I have no weight belt, holding my breath, and in 50 degree water. I could buy stuff for all those things, but again it'll quickly be $200-300.

If that's the cost of replacing an AutoProp zinc, so be it, but it just seemed silly to have to hire a diver for what should be a 5 minute job. I'm halfway tempted just to let the prop go without a zinc and buy a MaxProp at next haul out. That's 3k but half of that would be recovered in diving costs over 8 years.

[dkall]

It might be easier to remove the prop. There is a large nut under the zine which is now visible and a set screw on the side of the prop holding the nut in. Remove set screw, remove nut and remove prop. Otherwise the other replies might solve the issue.

[fstbttms]

Those ridiculous nylon screws are just one of the reasons I don't care for Autoprop.

As mentioned, it theoretically would be possible to drill out the broken screw with a pneumatic drill. If you choose to go this route, you will need proper dive gear, an air compressor with enough "oompf" to run the drill and of course, a pneumatic drill. I have bought cheap drills at Harbor Freight for this kind of thing. Expect to throw the drill out after one or two uses however. You could go to great lengths to preserve the drill after use, but how much effort are you willing to expend to save a $25 tool?

Your best bet is to hire an experienced hull cleaner to do the job. And have him change those stupid plastic screws out for monel screws.

[dkall]

While initially I thought those plastic screws were cheap I believe they are there for a purpose. However if you over tighten them they might break as indicated. As the zinc is eaten away the screws keep them in contract with the prop. Tighten them down flush and then put another 1/2 on them and that appears to torque them a bit. I don't know if the poster had been in a marina were there is little electrical action but if you change them every 6 months - a year or so the plastic will not have a tendency to harden and break. In 10 years I've never had one break off. And I use the new ones every time. I don't re-use the old ones. Now I know why! Good luck.

[a64pilot]

Use to be there was an adapter made by Islers diving I think that is all bronze with SS screws that mounts on the back of the Autoprop.
It takes regular standard B prop anodes.
The Autoprop anode is a great aerodynamic thing, but a terrible anode.
Many paint fingernail polish around the screw holes as the anode wastes away there first and falls off.
If all I had was an Autoprop anode I would use a Grouper anode that hands from a wire, great big anode that lasts years, but has to be removed and stowed when sailing of course.

[a64pilot]

I think fstbttms may know Islers diving, and of course this is plastic, a Yankee screwdriver or other manual drill will work, holes were drilled before electricity of course

[Frankly]

I purchased some SS versions of the zinc attachment screws (metric) and have been using them for over 10 years. I think they are better idea because they maintain the electrical contact as the zinc wears away.

Get a set of SS screws and attach the zinc with two of them and skip the sheared off nylon. Don't think you will have nearly the problems. Haven't lost a single zinc since I ditched those nylon screws and can see no issues with the SS. Mine is the earlier water lubed prop and the races and balls are also SS. Don't buy that the SS screws are adding to different metals issues.

Don't think the prop is brass but nickle aluminum bronze. One of the most corrosion resistant alloys around.

[Tessellate]

Originally Posted by a64pilot

I think fstbttms may know Islers diving, and of course this is plastic, a Yankee screwdriver or other manual drill will work, holes were drilled before electricity of course

A manual drill is a good idea and I've been looking for an excuse to buy one anyway (and they're only about $30). Yet, I still don't quite see how that's going to work, practically speaking. Every manual drill I've seen requires two hands to operate - one to turn the crank handle and one to apply pressure towards the thing you're drilling.

Underwater that will just push you away from the prop. So I would need to somehow tie myself to the prop/shaft (a terrible idea without breathing apparatus) or perhaps use one hand to simultaneously grip the drill and prop nut together.

I started calling a couple marine dive services but no luck so far. Even if I don't do it myself I'd like to understand how they would do it properly because I don't want some amateur diver from Craigslist hammering away on it and end up breaking something.

Pulling the prop is not something I want to do. The nut and/or set screw almost certainly will require lubrication and heat.

My bad on saying the prop is brass, I meant bronze.

[fstbttms]

You're considering doing this while holding your breath but you're worried about an "amateur diver from craigslist"?

[Tessellate]

Originally Posted by fstbttms

You're considering doing this while holding your breath but you're worried about an "amateur diver from craigslist"?

Well, yes, are you saying you don't care to know how someone is going to perform work on your boat, and would have no concern with whether they have qualifications or any marine experience at all?

[fstbttms]

Originally Posted by Tessellate

Well, yes, are you saying you don't care to know how someone is going to perform work on your boat, and would have no concern with whether they have qualifications or any marine experience at all?

Of course you want somebody who is properly equipped and experienced, that is why you are looking for someone other than yourself to do the job. I am not suggesting you hire just anybody and a quick glance at the Seattle craigslist Marine Services section shows there are quite a few professional outfits advertising there, any of whom could undoubtably handle this work.

[a64pilot]

Pulling a prop in the water is no big deal, and I would NOT put any heat on that prop when it's out of the water either, especially if it is one of the newer ones that is greased and has rubber seals.
Autoprop sells a special puller that fits that prop perfectly and makes prop pulling very easy, however I am certain that a special puller is not required, just makes it easier is all.
I would never try pulling myself without SCUBA, maybe thirty years ago, but not now.

[a64pilot]

Google Yankee screwdriver to see a one handed mechanical drill, get a cheap one

[fstbttms]

Originally Posted by a64pilot

I think fstbttms may know Islers diving, and of course this is plastic, a Yankee screwdriver or other manual drill will work, holes were drilled before electricity of course

Neither of the links I have for that particular anode adapter work anymore, so I googled it. I saw a picture of it, followed it to the source and it turns out it was one I'd posted in this thread in 2007! I've been making the same friggin' argument in the same friggin' thread for almost a decade!