Back to Bluebird today, bailing out the water we shipped last October and then sizing up the centerboard pivot bolt for some leak prevention. A friend, Peter Carter, suggested the use of 3M's 5200 caulk, the stuff that is supposed to never let go. I'll give it a try. A visit to Home Depot got me two pvc caps with screw-in lids, one for each side of the bolt. The plan is to glue the caps over the bolt ends with 5200 and then insert the screw-in lids to hold the water at bay. If the 5200 does, indeed, keep the pvc in place, that part of the problem should be solved.
I'd be happy to hear from anyone who may have used 5200 on pvc, or who has a better suggestion.