How much cutlass bearing play is OK?

[mbu745]

I was talking of a Morse bearing, not a Moss. They shoiuld be very tight around the shaft when instaled, mine was just lose. Willy

[seacap]

I had cutlass bearing problems that could end up costing me over 8K. you can read more at Bristol Channel Cutter

It's to long of a story to post here.

[OceansFive]

Originally Posted by Celestialsailor

The water does not lubricate the bearing by it's loosness. There are linear serations along the length of the cutless bearing that does this. A 1/16 or .062" play is excessive. When new, it should be a light slip fit. Either the bearing is worn out or the shaft is worn in the cutless area.

Congratulations on your retirement, may it be blessed with good health, great friends and amazing contentment. I

How you change the CB in Joli' Elle?

Dennison

ps I tried posting a comment on your website but it proved impossible.

[4HMainer]

Originally Posted by Celestialsailor

The water does not lubricate the bearing by it's loosness. There are linear serations along the length of the cutless bearing that does this. A 1/16 or .062" play is excessive. When new, it should be a light slip fit. Either the bearing is worn out or the shaft is worn in the cutless area.

A few facts are needed here I think, having run a business supplying bearings for a number of years.

Bearings for shafts (or rudders) that are emmersed in water or fed with water are water lubricated. any bearing that is lubricated by a liquid (or grease) needs a small clearance to allow a film of that lubricant to establish itself as the shaft spins.

The water ways or oil ways in an oil bearing are to allow a flow of liquid to aid cooling. A water film will support a surprising amount of pressure when the surface is moving, think of it like aqua planing when you hit a shallow puddle at speed, slick tyres and you'll aqua plane earlier, same with bearings fewer water ways and the shaft will float on a layer of water sooner.

So sorry to disagree with you celestial, but I think it's important for people to know that you do need a running clearance from new to allow this film to lubricate the bearing.

[GordMay]

Basically, you shouldn’t be able to feel any appreciable play.

USN Standards for Cutless Bearing Clearance ➥ http://www.pacificmarine.net/enginee...-clearance.htm

Johnson/Duramax specifies a “light press/interference fit” with 0.0008 to 0.0024" (0.02 - 0.06 mm) clearance.
➥ http://www.duramaxmarine.com/pdf/Fla...stallation.pdf

[HappyMdRSailor]

All of 'em great links Gordo...

[Blue Stocking]

If the vertically, or horizontally, opposed , fwd end to aft end, of the rubber insert are worn, indicates strut is out of line.