I doubt its you. Many won't do boats over 10 yrs. Commonly I here on used boats people have to put up, up to 25% of the boat value in order to get teh loan processed. The problem with boats is historically the boat payment was the first thing to slide when things get tight. The equity is the boat. Banks don't want to own houses, boats or cars. They definitely don't want to be in the business of selling them either. This isn't uncommon at all and I doubt it is you. I would bet if you submitted for the same loan for a car or house it would have gone through.
Don't take it personally.