Just use spring loaded automatic trailer bearing hubs. You over
pressurize the axle with grease (the spring compresses) and this keeps
the entire journal filled with grease .... and excludes water, etc.
You must let the bearings & journals 'cool-down' before you enter the
water (the sudden cooling with water will cause an internal vacuum
which will suck in water).

In article , Harry Krause
wrote:

Roger Long wrote:
Lots of sand. I would just use standard trailer components. The sand
problem won't be any worse than it would be for a boat trailer.

I dunno about that. I've been trailering boats for a number of years,
but I've always used decent ramps and never buried the axles in sand or
mud. Sure, there is some sand "in suspension" floating around, but if
you are launching by rolling down a beach in loose sand, it is going to
get into your bearings.


More hours
of immersion while the boat sits on a mooring will probably shorten the
life
of the underwater stuff so I will put zinc's on everything and just plan on
replacing things every few years.

I doubt you'll get a season out of metal axles and bearings.

There are some launchers around for PWCs that use large nylon or plastic
wheels and corrosion-proof axles. I don't know the particulars, but you
might want to inquire about these...

Good luck. Me, I'd grin and bear it with a decent inflatable and a pair
of tall fishermen's boots.