Prop Key - Stainless Only?

[four winds]

This is starting to nag at me. And I'm not even sure if I did this.

At haulout last January I may have installed a new prop key of regular steel from the auto parts house. I know I have that material in my coupling at the engine.

If I did put a steel key instead of stainless in the prop what could the results of that possible mistake?

My imagination runs wild and the anxiety builds. Fairly sure if I had the funds I would haul it and check.

Any opinions?

[Capt Hugh Wilde]

Originally Posted by four winds

This is starting to nag at me. And I'm not even sure if I did this.

At haulout last January I may have installed a new prop key of regular steel from the auto parts house. I know I have that material in my coupling at the engine.

If I did put a steel key instead of stainless in the prop what could the results of that possible mistake?

My imagination runs wild and the anxiety builds. Fairly sure if I had the funds I would haul it and check.

Any opinions?

The rust can jam the prop on the shaft.

However, the best material for a prop key is bronze key stock and not stainless.

Get a diver to take of the prop and have a new bronze key fitted to the shaft and prop and reinstall it.

You have 3 metals there now, steel in that key, stainless shaft, and a bronze prop.

As for using a steel key inside, the coupling is steel. So either a stainless key to match the shaft, or a steel to match the coupling.

When we have used bronze couplings we have used bronze keys.

Why would you use a steel key in salt water?

[four winds]

Why? No excuses. I made a mistake.

I may toss the boat looking for the stainless key that was there.

Or it may be back in place, I'm just not sure.

[Snowpetrel]

If you've got a prop shaft anode it shouldnt rust or corrode much, if any. Might have slightly faster anode loss. I personally would be pretty happy to leave it until the next slipage as long as the anode is ok. Assuming you're doing annual or so haulouts.

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[chris95040]

But to settle your nerves....

I believe the steel would be the least noble metal in that bunch, and it would be the one to corrode rather than the bronze prop and stainless shaft. I don't really have any experience to back that up, though.

Also, I've heard mention many times (here) that the friction in a tapered fit ultimately takes the torque of the spinning prop, and the key is just there as belt + suspenders.

With that in mind, personally I'd put it on the todo list but I wouldn't freak out about it.

[four winds]

Anode is still very good as of my hull and prop scrub a couple of weeks ago.

Actually good to me if it makes the prop harder to remove later. As I would be more concerned if it could cause a loss of the prop while in use. That was my main concern.

Not worrying now, about a mistake I'm not sure I even made.

[Wotname]

Originally Posted by four winds

Anode is still very good as of my hull and prop scrub a couple of weeks ago.

Actually good to me if it makes the prop harder to remove later. As I would be more concerned if it could cause a loss of the prop while in use. That was my main concern.

Not worrying now, about a mistake I'm not sure I even made.

I can't see anyway that it cause you to loose your prop.

It shouldn't have any effect on the prop nut and that is the item that keeps the prop on the shaft. Even the nut really only has any effect when going astern. Going forward, the prop is just pulled harder onto the taper.

To my mind, the bigger concern would be the steel rusting and thus expanding and so making the prop extremely difficult to remove.

I agree with those who suggest the shaft annode will keep the rusting at bay in the interim.

[a64pilot]

Just from a curious look around a couple of yards, I believe the majority of keys out there are the cheap zinc plated steel ones you get from the hardware store, the few yards that I have noticed seem to have the different sizes in bulk, wack off the needed amount with a hacksaw, and it's always been the cheap zinc plated steel stuff that I have seen.
I wouldn't worry, but might pull the prop next time I hauled the boat.

[mramoo]

I my search for a larger boat this is what I have come across. A very good reason to make sure that your Zinc's are in good shape.

[tdh1849]

Just a suggestion but get the tel# for, "Frank and Jimmys Prop Shop" in Ft.Lauderdale, tell them a former customer from Ft.Lauderdale now in Tampa suggested you call. They are one of the biggest and best prop shops in town and should answer any questions you have.
Tell them that they did my prop at their shop when I had the boat up at a yard known as, "Playboy Marine". Work was done in the yard by " Basil" now deceased.

[tinkrman69]

Rust creates 4000 psi. it doesn't take that much to dent bronze...in effect widening the keyway, not to mention making it really hard to get the prop off, and possibly having to use a slid hammer or using a hammer to pop a puller, causing damage to the thrust bearing in the reverse gear. Making the cost of a "maybe", quite expensive. If you manage to keep your prop/shaft zinc really clean you could be problem free till the next haul out. "maybe"

it's really easy to pull a prop in the water.

if the yards your using use zinc plate keys find another yard or don't let them do any work at all on your boat. I've worked at many yards and hauled out at many others and have never seen anything but bronze or stainless keys sold for props. they do sell steel woodruf keys and straight keys for pullies and the like. maybe your looking in the wrong shelf.

[Cadence]

Originally Posted by four winds

This is starting to nag at me. And I'm not even sure if I did this.

At haulout last January I may have installed a new prop key of regular steel from the auto parts house. I know I have that material in my coupling at the engine.

If I did put a steel key instead of stainless in the prop what could the results of that possible mistake?

My imagination runs wild and the anxiety builds. Fairly sure if I had the funds I would haul it and check.

Any opinions?

Bronze.

[four winds]

Tink, re your comment about 4000 psi.

That idea is what began to nag at me about this. Figuring that rust would expand and cause pressure on the prop keyway, causing damage or loss of the prop underway.

Can't blame the yard workers as I did this myself. And worse still I'm not even sure if I put the stainless key back in or a new key of inappropriate material.

This would be a good place for the well overused banghead emoticon.

[fstbttms]

Originally Posted by mramoo

I my search for a larger boat this is what I have come across. A very good reason to make sure that your Zinc's are in good shape.

Here's a better reason

[fstbttms]

Originally Posted by four winds

Fairly sure if I had the funds I would haul it and check.

There is pretty much no reason to ever haul out to simply remove or install a prop, regardless of type. This is something most hull cleaners can do easily and for much less than a haulout.