Shaft bearings

Is there a shaft bearing where the shaft log penetrates the boat? I find lots of info on Cutlass bearing replacement but not much on the hull penetrations. My guess is there has to be. Does it have a name?

Some are simply cutlass bearings .

On a commercial boat sometimes the stuffing/bearing is 15-20 layers of packing and adjusted to keep the water out.

Advantage , the packing/bearing can be changed while afloat from inside..

On bigger boats the stern bearing is oil or grease lubricated with seals.

Some boats there is a cutlass in the end of the shaft tube. Looks like yours is one.

When I built my boat, the span between bearings was too far so I needed a bearing between the strut and the tranny. Span about 9'. So I put a brg in the tube end just like the OP's pic.

Easier to do and less drag than mounting a strut to hull bottom.

Since loads were very low there, I bandsawed the brg in half and kept the other half as a spare.

If you look along the shaft towards the shaft opening you will see tiny ridges of rubber around the shaft where it penetrates the hull. Now gently scrape away the anti fouling along the side of the hull moulding where the shaft exits and you will see either one or more likely two tiny hexagon grub screws.
Remove these.
Disconnect the shaft inside, remove the drive flange ready to withdraw the shaft.
Lubricate the part of the shaft inside the boat with a strong soapy water mixture to aid withdrawal and do the same when refitting.
Remove the shaft.
Now you will be able to see inside the aperture either a brass or phenolic tube with a small coating of ridged rubber inside, that's the cutlass bearing.
Take a drift slightly smaller than the tube and gently drift it out, be sure to keep the drift 'square on'.
After the cutlass bearing is removed measure the inside, outside, diameter and length and re order a new one.
My tip would be to replace the old stuffing box with a PSS seal, far superior with virtually no maintenance other than periodic checking.
While the shaft is out get it checked for straightness and balance in a hydraulic ram repair shop and get your propeller checked for any repairs or balance.
Refit in reverse order with a light coating of copperslip (non seize grease compound) on mating metal surfaces.
When finally connecting the drive flange to the engine make absolutely certain sure the engine/shaft alignment is nothing less than perfect.


Near enough simply isn't good enough.


I would check engine mountings and the clutch drive plate while everything is stripped out.

The extra effort you put in now be well rewarded with many years of trouble free cruising.
I hope this is helpful to you.

Thanks everyone for the feedback.
Irish Rambler, my question was based on the fact that I just had engine mounts replaced and asked the yard to check my cutlass bearings while they were doing the mounts. Cant say I share your view on the PSS. I will take the simple packing that I have. I have a friend that had a PSS seal failure in some pretty bad conditions. I will keep it simple.

The only thing I would be very particular about would be checking the shaft/engine alignment when your boat's back in the water.
I've never had a problem with PSS shaft seal but whatever your comfortable with and have peace of mind is fine.

GFO marine packing. Been using that for years. My shafts were pitted and the flax always wore and leaked after every use. The GFO does not do that, mostly does not drip at all.

sdowney717 said:

GFO marine packing. Been using that for years. My shafts were pitted and the flax always wore and leaked after every use. The GFO does not do that, mostly does not drip at all.

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Same here, I shifted 4 years ago and haven't had a drip or adjusted the packing. Its been running cool since run in.

fryedaze said:

Same here, I shifted 4 years ago and haven't had a drip or adjusted the packing. Its been running cool since run in.

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It lasts forever, It has been in since 2006, the same piece, on two shafts. I also used it on the rudder shafts.