Is blistering normal under trailer bunks? I was just told that my 93 Outlaw had some blisters under the bunks. Is this just something that happens with older boats?

It can happen to almost any boat actually. Some seem to have problems with it from time to time Donzi has had some, Baja, I am sure a lot of others too. A lot of people probably have them where their bunks are and don't even know it.

Not saying it is right, but I am sure it happens a lot. There are several well written articles on the web about how it happens.