Boat Issues-Epic Fail
Q: All else has failed--it just won't work! What do I do now?
"When all else fails, read the instructions." -Unknown
Second Life has been known for a lot of things, but stability and consistency is not among them. Something that works fine one minute may fail catastrophically the next. And visa versa.
Maybe there's a griefer nearby, or maybe the asset cluster has just taken a vacation. My best advice would be to try doing what you're doing in another sim, far away, perhaps at a different time, and see if it fails in the same way.
And when all else truly fails, go outside and play.