Prop Shaft Leak

[MicHughV]

those two surface are lubricated with water....that's the whole purpose of the bellow...you want some pressure between the two discs, but not a lot...the bellow should be able to be moved back with one finger...

[MicHughV]

you'll get some water inside the boat, when you pull the bellows back, but that should stop the minute the two surfaces are mated up again..

[jamrocksailing]

Originally Posted by MicHughV

the fact that the screw driver placed under the bellows stops the leak, would appear to indicate that the two surfaces are not mating properly, a situation compounded while running....what is causing this is hard to say without being there...

I would try to run the engine in gear while docked with the screw driver in place...maybe the bellows are worn ??

I noted the high speed version, but not sure why a sailboat has the high speed version, usually that little hose provides added water pressure from the outside due to high speed, as water can get sucked out of the bellows at high speed...that little hose is usually fitted with a little scoop over that little pipe outside of the hull to help feed water to the bellows.....I don't think that little hose is to bleed water and certainly not air to the outside of the hull....but in this case, it could also be venting water pressure to the outside of the hull...?? Maybe some little something got into that little hose and found its way to the bearing surface.

These are some of the things, I'd be checking....as well as possible dirt, debris, etc...

my first inclination would be to pull the bellows back to see if there was any small piece of shell, seaweed, something...interfering with a good seal....but the fact that the screwdriver stops the leak might indicate a problem with the bellows...

Unfortunately the boat must be hauled to check or replace this....could be done with the boat in the slings.....but I'd try to do some diagnosing sleuthing while the boat is in the slip...

Hi thanks, I went back the next day as the screwdriver was a temporary solution and looked at it in detail. I pulled the bellows back let is flush out and lightly sanded to remove any debris.

It is now sealed without leaking but have not started the engine as pulling the yacht out early February and will be replacing the unit. This weekend I am going to place in gear and see if it still leaks as will need to drive round to be hauled up and need to ensure it can do that.

Did not want to do it before as dried up the bilges etc and cleaned it all. I think it has been dripping for a while.

There was soundproofing on the underside of the floorboard and this was worn, I think the steel ring was rubbing against this which was not good. I have removed this and the glue etc to make it all clean.

Wish me luck as need to install the new one now.

D