KK42 Cutlass Bearing

We have been stuck in Georgetown Exuma for two months finding a manifold for our Lehman 120. Once I found one it was a month in shipping and customs. Its installed and we are very ready to head back to Florid. We were getting ready for a test ride and heard a rubbing thump sound once we put it in gear. Forward and reverse. I can turn the prop shaft easily by hand. The shaft does not look bent. I'm not a diver so getting the bottom cleaned during lockdown hasn't been an option. I cant get the stuffing box to drip so I believe the cooling water intakes for the shaft are plugged with growth. My question, Has anyone cleaned the intakes and the cutlass bearing in the water? And advice on how? We really need to get out of Georgetown before Hurricane season and the Gods are not helping. Thank you for any advice.

Scott
M/V Lemonade
KK42-016

If you can turn the shaft easily, is the cutlass bearing a problem? Have you undone the stuffing box and checked your packing, ie, pulled some back. Undo the nut and pull some packing and I bet you get water coming in.

Also, after two months of no movements in tropical waters, I’d find someone to at least clean the running gear.

Let us know what you find out.

I have been able to clean the prop, rudder, and most if the bottom. Not the keel so much. So they aren't terrible.

There really isn't anything to go wrong on the prop shaft but the cutlass and stuffing box. Is this correct? I checked the space between the zinc between the cutlass and prop. Its clean. So I'm thinking maybe a rough shaft in the stuffing area? I wont run the boat till I sort this. At this point I have turned the prop maybe 25 rotations each direction. Not a lot.

Could it be the damper plate?

Can you disconnect the prop shaft coupler and move the prop shaft back a bit so there is a gap between the transmission coupler and the prop shaft coupler? If you do then you can run the engine in forward and reverse and see if the noise is in the transmission or not. If the noise is still there then it could be the damper. If the noise goes away then the problem is in the stuffing box or the shaft. Good luck, hope you get it going.

Separated the prop shaft and trans. Trans is good. No noise there. Definitely in the prop shaft. I can turn the prop shaft easily hand but with the engine it grinds bad. Is it possible the cutlass bearing spun in its housing? If so would I be able to spin the shaft by hand? Doesn't seem likely. Scratching my head. I turned the prop at least 100 time each direction thinking any growth would come off. No change.

Do you have access to a stethoscope or even a piece of dowel? See if you can track down where exactly the noise is. Can you put someone in the water and have them look at the backend of the shaft/bearing as you turn the shaft by hand? While they are in the water have them inspect the prop as you turn it.

Disconnecting everything is a good test but not conclusive since it’s not loaded up with the propeller.

We’ve had a cutlass bearing separate on a previous boat only because we had a line wrapped around the shaft. The only way I knew I it was at low rpms and we had a high pitched noise. As the rpms increased, the rubber grabbed the bronze outer sleeve and stopped slipping.

If the boat had been sitting there, I don’t think the cutlass bearing would just fail.

That is strange. I guess it may be a cutlass bearing...

Got thinking about this. When our cutlass bearing failed, the play in the shaft was extremely noticeable. By grabbing the prop, you could move the shaft maybe 1/8” to 1/4”.

I checked the prop all good. Cant find any mechanical reason for the noise. So we took the boat for a one hour ride. All the noise is gone. So I either destroyed something expensive or I got some growth removed. The boat running perfect at the moment. Now to get back to the states.

Thank you all for the insight. I really appreciate it. Full timers for 10 months. Lots to learn still.

That’s great! Have a safe trip back.

It probably was some growth on the shaft. Congrats on getting it fixed.