Lose Zinc

[nauticalrich]

Just hauled the boat out and noticed one of the zincs had completely either broken or worn off and it was wabbling on the shaft.

Never noticed it when it was running and no damage.

The other zinc on the shaft was fine.

It borke off where one of the screws is at.

Anyone experienced this and know how to prevent it in the future?

Maybe the zinc was a piece of sh####t.
Bought it from Cap''t cove marina and assume it must be good quality. I paid enough for them.

[Silmaril]

That is what a zinc should do, wear out! They are "sacrificials" and give up their life in the valiant defence of much more expensive items, like props, shafts, struts, and the like. If you feel you are going through them too fast, you might look at your electrics. Stray currents from an un-isolated shore power connection could be eating them up. Just be happy you are just replacing zincs instead of the more costly items.

I now go through two "bullets" a year on my prop shaft, four a year before I put the galvanic isolator on line. I was having to dive over and replace them underwater halfway though the season. But you should give them a monthly "look-see" just to make sure they are fine anyway.

[graham1]

Besides the fact that the zinc is <supposed> to wear out, be sure that you don''t have a metric shaft. I once tried to put a one inch zinc on a 25mm shaft - I couldn''t tighten it. That extra 0.4mm makes a big difference (1" = 25.4mm). The first time my diver replaced it, he did the same thing.