Prop shaft zinc

[Avoegeli]

How much space does the cutlass bearing need? How much space for the water to lubricate properly? Here is a picture of the zinc I installed today. I ground down the sides to get it to fit. This is the prop shaft of a contessa 32.

[MicHughV]

That gap between zinc and bearing seems mighty small to my eye....an 1/8" by my guess.

When the engine is in forward gear, and you bring it up to rpm the prop will want to push the shaft forward and that zinc might end up rubbing on the cutlass bearing;
It might also prevent water from getting inside the bearing, which provides the "lubricant" for the bearing.

I would consider buying one of these rubber flange couplers, which will fit between the engine flange and prop flange. This will push the prop back 1/2" or so, allowing for some more clearance here.

[fstbttms]

Honestly, I suspect that gap is enough. I see many boats with a similar setup. But if you’re uncomfortable with it or feel the cutless isn’t properly lubricated, this is an alternative

https://www.boatzincs.com/LC-3.html

[Avoegeli]

Originally Posted by fstbttms

Honestly, I suspect that gap is enough. I see many boats with a similar setup. But if you’re uncomfortable with it or feel the cutless isn’t properly lubricated, this is an alternative Attachment 274531

https://www.boatzincs.com/LC-3.html

Thanks I saw this today. I think my boat is being launched on Wednesday. It wouldn't ship in time. I think tomorrow I will go and take the angle grinder to the one I have and buy myself another 1/16" on each side fore and aft to get another 1/8" of clearance. Just for peace of mind. Thank you for your thoughts and suggestions

[Emmalina]

Prop nut not looking too happy is that also an anode ? I have one on the nut.

[SVTatia]

Originally Posted by Emmalina

Prop nut not looking too happy is that also an anode ? I have one on the nut.

Is this custom made? If not, where to find them? I assume they use the shaft threads or do you need that much shaft after the prop?

[Emmalina]

Originally Posted by SVTatia

Is this custom made? If not, where to find them? I assume they use the shaft threads or do you need that much shaft after the prop?

Thats how it came but with a much smaller anode that didn't last very long and was very expensive. I cast my own now.

[Avoegeli]

Found a couple options that fit correctly. I installed both. Thanks for help and advice from everyone here. What a great resource this website and forum is 🙏🏻

[Avoegeli]

Originally Posted by Emmalina

Prop nut not looking too happy is that also an anode ? I have one on the nut.

Prop nut is fine. Just got some anti fouling on it. I bought a micro zinc for the shaft and a prop nut type anode.

[SailingHarmonie]

The issue here is that the engine is not fixed in position. When the prop is driving the boat forward the engine mounts WILL flex and the whole drive train then moves forward.

There ARE thinner shaft zincs available. I would get one. The standard numbers I have seen are to be sure that there is 1/2" minimum clearance behind the cutlass bearing and any rotating pieces on the shaft while at rest. That is NOT for "circulation" but to allow for movement of the mounts under thrust loads. That is a standard number, it is conservative. Your engine MIGHT move less... or not.

I don't know what people think is required for "circulation" in a cutless bearing in this configuration. There is no place for the water to go. Water doesn't "circulate" through it. As long as it can fill with water, it is good. No way the zinc is going to create a water-tight seal on the aft end of it.

You need more clearance, but for a different reason than people are guessing.

[boatpoker]

Originally Posted by SailingHarmonie

The issue here is that the engine is not fixed in position. When the prop is driving the boat forward the engine mounts WILL flex and the whole drive train then moves forward.

You need more clearance, but for a different reason than people are guessing.

I agree, this is what happens when motor mounts go bad.

[fstbttms]

Originally Posted by boatpoker

I agree, this is what happens when motor mounts go bad.

This is also what happens when the prop moves up the shaft because it was never properly set when installed.

[pcmm]

Originally Posted by Avoegeli

How much space does the cutlass bearing need? How much space for the water to lubricate properly? Here is a picture of the zinc I installed today. I ground down the sides to get it to fit. This is the prop shaft of a contessa 32.

The rule of thumb is generally 1 - 1.5 shaft diameters of space. Get rid of the donut zinc and use a prop nut zinc like this:

https://www.westmarine.com/martyr-ca...2_003_004.html

[MicHughV]

The cutlass bearing could also be inserted a bit more to create more space.....although I'm a fan of leaving a 1/4" exposed, so that I can wrap a big wrench around it to remove it when the time comes, without removing the prop shaft.

I've seen some keels that have a hole in the shaft log to allow water inside, not sure if this boat has that...

Several options posted here for consideration.

[MicHughV]

Never seen a forklift being used as a travel lift before...pretty nifty...
Your new zinc setup looks perfect.
Happy sailing