As a motorcyclist, I am wary of boats on trailers, you never know when a
wheel will come off, or what will pop out. I watched a life jacket float
around in one for a few miles, then it popped up, the wind caught it and
it's strap brought a 6 foot wooden oar with it. One of my friends was killed
by another negligent boater on the road.

Wheel bearings get warm when you use them. When you dunk them in cool water,
everything contracts and it sucks water in. The water pits the bearings, and
then they continue to get worse like a pothole in the road. This happened
to yours, replace them all.
This can be avoided by installing the grease seals backwards, so grease can
escape but water won't get in, and replacing the caps with "Bearing buddys",
or "bullseye" caps. They have a Zerk fitting and hold the grease under
spring pressure, and any excess is pushed out behind the wheel . I have
found the Bullseye leaks less grease film. They may make a small mess, but
being stuck along the roadway with a ruined spindle, or causing a wreck, is
far worse. Use a waterproof grease, and never mix it with another type.
--
Stupendous Man,
Defender of Freedom, Advocate of Liberty