Cutlass bearing

[Crash]

How can you tell if a cutlass (sp?) bearing needs to be replaced? The original owner replaced it about 9 years ago and the reason being was...just because it was a 20 year old boat. I personally don't see any "issues" but I will inspect the prop as soon as she's hauled out.

[RUSSELL]

Crash,

I am a newbie, but I would think you would evaluate as any other bearing:

(1) Any scoring on the friction surface (the propellar shaft)?

(2) Bearing snug in the strut (housing)?

(3) Ample bearing material; not excessively worn?

(4) Does the propellar shaft fit within tolerance; is "play" within reason?

I can't see why you would replace a cutlass bearing if these check out, regardless of how old it is.

My cutlass bearing has rubber components. I suppose those will fail eventaully; I have no idea how long they should last.

I don't know if I am missing something here.

[CalebD]

How can you tell if a cutlass (sp?) bearing needs to be replaced?

Do you feel any vibrations coming from the engine when underway? the shaft? Does the shaft make any noises at different rpms? Is there 1/16" or more of play between the shaft and Cutlass bearing?
If you answered yes to any one of these questions then maybe it is time to check your Cutlass bearing, engine mounts and shaft coupling.

The original owner replaced it about 9 years ago and the reason being was...just because it was a 20 year old boat. I personally don't see any "issues" but I will inspect the prop as soon as she's hauled out.

I'm not an expert but Cutlass bearings need to be replaced from time to time. I'd guess the average lifespan of one is < 20 years but could be longer if engine alignment was good and engine had low hours of usage.

Stuff needs to be replaced on older boats.

How old is the packing in your stuffing box? I'd look at doing that first as it is much easier to do, usually.

[ILikeRust]

It's spelled cutless. So-called because unlike the older bronze bushings, which could score or cut the shaft if grit got in there, the neoprene liner helps prevent scoring or cutting of the prop shaft. Hence, it is a "cutless" bearing.

To see how "bad" it is, with the boat out of the water, grab the prop and see how much you can wiggle the prop shaft around in the bearing. If the shaft moves around within the bearing, it's shot. It should be a sort of snug fit and should not rattle around within the bearing.

[tenders]

Cutless bearings are part of a general type of bearing called "stave bearings" which were originally lined with fore-and-aft strips, "staves," of hard wood, which were lubricated when immersed in water.

Cutless is, or was, a brand name for the bearings that use neoprene instead of wood. I think the adhesive bonding the neoprene to the bronze bushing was a key component to the technology.

Support bearings inside the hull, often seen on ships with long shafts that need support along their run, can be cooled with oil and are lined with soft metal called babbitt.

[Crash]

todays yard work

Dionysus was pulled out this morning so I made my way down to inspect the prop and shaft for "wiggle". Sure enough there was wiggle..even the yard boss came by to report I needed to change out the cutless bearing.

CalebD: I actually needed to replace my stuffing box as the PO switched it to a PSS (dripless) type shaft seal. I had a slight leak which was made worse by an exhaust hose tangled onto the shaft where the wire reinforcing made its way between the seal and leaked profusely. I was slowly sinking. BUT now I have a new cutless bearing (the yard used a hydraulic press) and a new conventional stuffing box. Tomorrow its onto the traditional bottom sanding mania and new bottom paint!

Oh BTW the whole stuffing box/cutless bearing repair took less than an hour.

[joe_db]

Mine had about 1/4" clearance between the shaft and the bearing. The new one holds the shaft snug.

[wmmulvey]

Cutlass Bearing Removal

Never done this before. How do you remove a cutlass bearing?

Are the bearings on both ends or do the bearings run the length of the housing?

TIA

Bill
1969 Morgan 30

[ILikeRust]

How you remove a cutless bearing depends on whether you've got a separate strut that supports the aft end of the prop shaft - in which case, the cutless bearing is housed in the strut - or whether you've got a full keel with shaft log, in which case, the cutless bearing is housed inside the deadwood.

For one example of how to pull a cutless bearing out of a strut, see here.

The cutless is one big, long "bearing." It's not what I typically think of as a bearing (i.e., it's not a ball bearing or roller bearing). It's a bronze tube lined with neoprene.

Here is an assortment of various sized cutless bearings:



Here's another "how to" page.

Mine is located in the stern deadwood, so there's no way to pull it out using the methods shown for a strut. I was fortunate, though, that mine came out pretty easily. I put a couple nuts on the end of a threaded rod, which would fit through the bore of the bearing. I inserted it far enough that the nuts caught on the inside end of the bearing. Then I pulled the threaded rod, sort of like a slide hammer and tap, tap, tapped the bearing out of the stern tube.

[wmmulvey]

Re: Cutlass Bearing Removal

Got my answer through a little more research.

Bearings are not bearings at all.

Still would like some more removal ideas. Mine is not a strut, its a hull


TIA

Bill
1969 Morgan 30

[ILikeRust]

Check out the second link I posted above.

The typical method I encountered - and that the boatyard told me they would use - is to use either a hacksaw blade or, if you're more brave and have a deft hand, a sawzall - and stick the blade into the center of the bearing and cut a slot lengthwise from the inside towards the outside, but stop just shy of actually cutting through the bearing shell, to make sure you don't cut further into the fiberglass. This leaves a tiny, thin sliver of bronze.

Then use a cold chisel and hammer to pry the bronze shell inwards, to shrink it in diameter. Once you get it collapsed, you can pull it out.

As I mentioned above, I was fortunate enough that mine was not such a tight fit - so I was able to tap mine out in one piece - it slid right out pretty easily, actually.

And don't forget to check for, and remove, set screws first.

[smosher]

I have 2 metal shims that sit on the shaft and I tap out the old bearing.

Lather up the new bearing in grease and slip it in.

Steve

[wmmulvey]

Re: Cutlass Bearing Removal

THANKS FOR ALL YOUR HELP

Bill
Morgan 30

[Don Moyer]

I'm trying to assist someone who's replacing his stuffing box assembly. Does anyone know the Coast Guard requirements for the hose? Specifically, does it have to be steel reinforced, or can it be a more flexible hose as long as it's approved for below waterline use. As I think about it, the very flexible rubber hoses used on drip-less prop shaft seals certainly aren't steel reinforced, so I may have answered my own question. Thanks, Don

[ndutton]

Lather up the new bearing in grease and slip it in.

Another trick is to pack the new bearing in ice in a cooler right before installation.

Don,
I've never seen wire reinforced hose used in this application. The hoses I have seen have maybe double the braided reinforcement though.