Re: rivet replacement.
if it's in hull outer skin and below water line, yeah, go with the bolts. blind riveters generally use hollow rivets, not so good for water resistance.
before you yank anything, though, try just rebucking the rivets....you, a friend, and 2 sledges, it's a beautiful thing. a little thinned epoxy resin poured around em on inside of hull (not worth buying a whole quart of Gluvit for this job) and call it good.