A seized cutlass bearing isn't fun

[bsangs]

Had an interesting and significant issue while getting a new prop installed. The cutlass bearing had completely seized to our prop shaft. Won't drown you with all the laborious details of how it was finally removed, but it's been replaced, and the strut and shaft were inspected and said to be structurally in tact. Hopefully the transmission is as well.

Have no idea when the seizure occurred, though it may have been a reason for the weird vibrations we felt at times during low forward RPMs last season. In August of '23, a leaking shaft seal was replaced, and the cutlass wasn't seized then, so this clearly developed sometime since. Any theories as to how that happens, and what is the general lifespan for a cutlass bearing? We do keep her in brackish water year-round, if that plays a role. (The previous owner pulled her every winter.) Will obviously be something I keep a closer eye on moving forward.

 

[Loren Beach]

The cutlass bearing had completely seized to our prop shaft.

Just to ask a naive question: so when you started the engine and it ran normally in neutral there was no problem. When you put it in gear and the shaft should have turned, it instantly (!) died? Wow!

 

[bsangs]

Just to ask a naive question: so when you started the engine and it ran normally in neutral there was no problem. When you put it in gear and the shaft should have turned, it instantly (!) died? Wow!

No, not at all, Loren. Never died. In fact, late March in my slip after de-winterizing, I turned it on, let it run for a bit, then shifted to both forward and reverse as I normally do, the prop engaged and she moved as normal. Again, there was some vibration at the lower RPMs, which I'd simply grown accustomed to. This seizure wasn't discovered until she was pulled for the new prop installation. (We were traveling in Europe during April while the work was being done at the yard.) So it would appear it was spinning in the strut while seized to the shaft. This is where I have to admit ignorance, because I'd honestly never paid much attention to the workings of the cutlass. I've gone down a rabbit hole since, however.

 

[Frank Langer]

Our cutless bearing has been in place for 20 years of our ownership, and still looks fine with no real looseness or play room, but spins freely.
Frank

 

[Prairie Schooner]

No, not at all, Loren. Never died. In fact, late March in my slip after de-winterizing, I turned it on, let it run for a bit, then shifted to both forward and reverse as I normally do, the prop engaged and she moved as normal. Again, there was some vibration at the lower RPMs, which I'd simply grown accustomed to. This seizure wasn't discovered until she was pulled for the new prop installation. (We were traveling in Europe during April while the work was being done at the yard.) So it would appear it was spinning in the strut while seized to the shaft. This is where I have to admit ignorance, because I'd honestly never paid much attention to the workings of the cutlass. I've gone down a rabbit hole since, however.

Sounds like the 'rubber' insert separated from the metal sleeve of the bearing assembly. Is that how you understand it?

 

[bsangs]

Sounds like the 'rubber' insert separated from the metal sleeve of the bearing assembly. Is that how you understand it?

I believe so? Or it generated enough heat to fuse it. But why? Shaft was aligned properly. It certainly was never run dry. It was in good shape when it was surveyed in early '22, and again when the shaft seal was replaced in '23. Puzzling. They had a devil of a time removing it, as they wanted to avoid the expense and effort of having to drop the rudder, remove the shaft seal, disconnect from the tranny, etc.

 

[Dave G.]

My guess would be something got stuck, seaweed, plastic bag, old shoe, lol & blocked the waterflow long enough that it got too hot. Heat is the only thing I can think of that would cause it to swell up around the shaft.

 

[bsangs]

My guess would be something got stuck, seaweed, plastic bag, old shoe, lol & blocked the waterflow long enough that it got too hot. Heat is the only thing I can think of that would cause it to swell up around the shaft.

Sure am glad I pay a diver monthly to go down there and check things.

 

[Christian Williams]

Well, the bearing is just a force fit into the strut, no? Apparently the rubber got stuck to the shaft and just spun with it?

Really, though, it's great to come out with the same shaft, cutlass and coupler. I am told that old boats can often expect to need a new shaft and shaft coupler whenever the shaft is yanked, which was the case for me. (The prop shaft tapers as it enters the coupler, with a key to secure it. Over the years the keyway gets banged up from normal use, and the shaft usually can't be saved. True of big ships, too, I was told. New shaft for the E381 was $1000.

Here's a video of the shaft/engine connection that I found useful.

 

[bsangs]

Well, the bearing is just a force fit into the strut, no? Apparently the rubber got stuck to the shaft and just spun with it?

Really, though, it's great to come out with the same shaft, cutlass and coupler. I am told that old boats can often expect to need a new shaft and shaft coupler whenever the shaft is yanked, which was the case for me. (The prop shaft tapers as it enters the coupler, with a key to secure it. Over the years the keyway gets banged up from normal use, and the shaft usually can't be saved. True of big ships, too, I was told. New shaft for the E381 was $1000.

Here's a video of the shaft/engine connection that I found useful.

Well Christian, I certainly hope I don't find out the hard way that they were incorrect about the shaft and coupler still being in good condition. That would be unfortunate, and surely would happen while transiting the Cape Cod Canal later this season.

 

[Christian Williams]

They would have loved to sell you more work. Sounds like you'll be fine.

 

[peaman]

One source cautions against installing shaft anodes too close forward of the shaft bearing, as that could impede necessary water flow. They recommend a minimum of 12" between anode and cutless bearing.

 

[bsangs]

One source cautions against installing shaft anodes too close forward of the shaft bearing, as that could impede necessary water flow. They recommend a minimum of 12" between anode and cutless bearing.

That is great info. Thanks peaman.