"Alan Pond" wrote in message
...
Had my bottom painted last week and the yard also put a new zinc on the
propeller shaft. I'm sure it doesn't sit 'right' and that I can feel the
shaft wobbling at anything over 2000 rpm.

What can I do about it?

Molesworth

Could be a metric/inch anomaly.
My boat has a 1" shaft but the only zincs I can buy are 25mm and they do
not sit right.
I get over this by bolting them on tightly and then hammering them together
tightening the bolts as I go until further hammering fails to loosen them
further.
The zinc is fairly soft but you must of course hold a heavy weight hard
against the back of the zinc to absorb the hammer blows and protect the
shaft and its bearings from stress.
Done this for several years and never had any problem with vibration or
loosening.