Pink propeller

[johna]

Lifted out today for annual wash and brush up. Propeller decidedly pink but not damaged in any way. Anode, new this time last year, 20%+ eroded so is working on something.

Two points:

Danger of not replacing the propeller, will it suddenly disintegrate or go on for years to come?

What is an acceptable level of resistance between anode and prop.

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[Chris_Robb]

1. If you hit it gently does it still have a good metalick ring??? if so propably OK.
2. More importantly you must locate the source of the problem - and check you seacocks as well. If in a Marina is it a pontoon leak - or another boat???

For more help you may need to contact MG Duff - who should be helpful.



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[ChrisE]

Does it go \'ping\' when you bash it?

Our prop went the same way and we replaced it on the advice of the yard. Their touchstone was that the prop was knackered if it made a dull sounding noise when tapped with a hammer. They reckoned that by the time it sounded like that it would fail witihn a season. Ours sounded distinctly dull so we replaced it.

Don't ask me the physics or the engineering but I trust the opinino of guys at the yard over my own scant knowledge.

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[boatless]

The reason it's gone pink is that the zinc has departed...

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[steve_cronin]

Yes MG Duff have published some comprehensive and informative literature on galvanic action and anodes.

If this has been berthed in a marina with the shore power attached (or even without it in some cases) then is a case for checking the bonding between fittings, the engine and the anode(s). Fitting a Galvanic Isolator is also very wise if the boat lives in a marina. However it also looks like a tale of "the horse has bolted" to me.

I saw a disintegrated P bracket once that had suffered de-zincification. The proshaft flailed all over the place, ruptured the Volvo seal and flooded the boat. With an eroded propellor you might be lucky and it might just fly off and sink" (but you'll be in need of a tow home if there isn't any wind)

Get it surveyed but sadly I think you might be in the market for a new prop.

Steve Cronin

<hr width=100% size=1>The above is, like any other post here, only a personal opinion