Cutless Bearing-:Has it Failed?

[paulrossall]

My cutless bearing is housed in a 4 inch stub which comes out the back of my skeg keel. (30ft sailing boat).Where the stub mates up to the keel was some sikoflex like seal which was coming loose. I cleaned it off and found 3 small holes each side and have now realised the stub should probably have been water cooled during these last 2 years I have had the boat. Cutless bearing was new 2 years ago when boat was bought and engine has done 250 hours since.
I have 1 inch prop shaft. There is 15thou play between prop shaft and bearing and shaft is not bent. Will the lack of water flow have caused the bearing to wear and does cutless bearing need replacing? If so are they always held in by grub screws as I cannot see any.
I thought I knew a bit about most boaty things and cannot believe how much I seem to learn every week reading this forum|
Thanks in anticipation of help. Paul

 

[AndrewD]

15 thou is not excessive. "The book" says Cutless bearings can have up to 1/16" of play which is about four times that much, so your bearing is probably OK if that's the only problem you have noticed. If the cooling channels are blocked it could still get the lubrication it needs; my boat has a mechanical shaft seal lubricated by cooling water, the waste water goes down the stern tube into the Cutless bearing, so the seawater channels aren't really needed. If you have a stuffing box, then the seawater channels MUST be kept clear since they are the only means of lubrication. If you do need to remove the bearing, the "stub" you mention is possibly threaded onto the aft end of the stern tube, so once the securing screws are removed it might well just screw off. Naturally the prop must be off (or the shaft removed) before you can do that. Not all Cutless bearings are secured with grub screws, though perhaps they should be. If you need a new one, the sizing is critical. It MUST match your shaft. You can always get the outside machined to fit the boat, or the "stub" on the boat machined to fit the bearing - that's what I did. It should be a firm fit, but not an interference fit, since it will distort easily. Good luck.

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[dickh]

Almost certainly the cutless bearing is secured with probably 2 grub screws - scrape all the antifouling away and you should see them - possibly used hex. socket grub screws and the holes have got filled with grease/dirt/antifouling - usually on the side (is on mine).

<hr width=100% size=1>dickh
I'd rather be sailing... /forums/images/icons/smile.gif