I come across some awful bodges perpetrated on boats from time to
time, and some bizarre uses of silicone sealer, but this was a new one
I'm renewing the 2" dia prop shaft & bearing on a 70 year old boat,
the old one had about 1/2" of play in the bearing. The bearing is
about 10" long, cast iron with a bronze bush.The shaft probably ran
originally directly in the cast iron, lubrication is by water or a bit
of grease if you're lucky.
I'd noticed a build up of crud at the inner end of the bush, where the
shaft isn't free to wave about as much as the outer end. A bit of
investigation found this to be RTV silicone - it seems that someone
had injected silicone sealer into the bearing to try to reduce the
play!! Maybe there's some fancy silicone sold for this sort of job?
I've no idea whether it had ever done any good, but it certainly
wasn't by the time it came to me. The bearing, judging by the state of
the retaining studs, hadn't been out for at least 15 years. The
silicone must have been injected via the greaser union!
There are 'rubber' prop shaft bearings available, but AFAIK they are
neoprene, and made with longitudinal flutes and arrangements to ensure
a flow of water from one end to the other. I'm not convinced about RTV
silicone as a bearing material, even under water.
A lot of boat repair can be described as bodging (doing the best you
can in the circumstances/with the money available), but I like to
think mine are of a better class than this
Traditional & Modern canal craft repairs
Vintage diesel engine service
17 years ago