To keep the shaft aligned, and provide support, it is held by two sets of bearings – one supporting the gearbox, fixed inside the boat, and the other either in the sternpost or in a P or A bracket extending from the hull.
The bearings in the gearbox or the boat provide both thrust and radial support. The outer bearing provides only radial support. The outer bearing is normally of the cutless type in which the shaft turns inside a rubber sleeve, grooved to assist water lubrication and bonded to a bronze outer sleeve.
Some internal bearings need a supply of water to keep them lubricated, in which case a feed line will have to be plumbed in.
