A more recent development in bearing materials is a phenolic based self lubricating bearing material known as Maritex Aquarius. This has advantages over UHMW plastics in that it is non melting/softening and can support high loads with less distortion, it also has surface chemistry to resist marine growth. It is being used in everything from the Panamax project to new submarine shafts and dive planes, but is also available for shafts from 1" to over 22". It can be used with water, oil or dry.
It machines without dust or fumes and is dimensionaly stable over a wide temperature range. Clearance calculators can be found if you search for maritex aquarius calculator