cutless bearing

[Guest]

How long should one be expected to last when sail cruising with say 100 hours motoring per season but often in heavy seas against tides.
what causes their failure and are there early warning signs before the big clunk and rattle.
apart from vibration risk to gearbox and engine mounts what other damage can occur if used with no soft bit left.
30mm shaft heavy Abracket, steel hull etc

 

[oldharry]

The life of cutless brearings depends very largely on where you sail. In good conditions they can last many hundreds of hours, but if you sail in water that has a lot of sediment or sand in it then the life will be proportionately reduced and can be as little as 150 hours. This will be further accelerated if there is inadequate water supply through the bearing - though on a P bracket this shouldn't be a problem.

Damage resulting from a worn bearing is intially caused by vibration as the shaft slops around - bearers, bearings etc all disliking being shaken about.

Do not leave the bearing unchanged so long that it wears right through to the metal housing. By then you will not only have wrecked gearbox and thrust bearings, but almost certainly the shaft itself will be damaged, and there is risk of breaking it altogether as it whips and flexes around. The P bracket will almost certainly be loose and leaking if it has not broken, and could well be damaged as result of the battering the shaft will have given it.

If you find you can rattle the shaft within the bearing (sideways displacement of at most 1 - 2 mm) then the bearing should be replaced. That sideways movement will be taking place on every turn of the shaft! ideally replace the bearing as soon as there is any sign of play.

 

[vyv_cox]

My cutless bearing has not been changed by either me or the previous owner, so it is at least 10 years old. From examination I could believe it to be original, boat is 1985. There is no play in it whatsoever.