I'm about to pull the trigger on a Deck boat . It's 22 years old , but looks well cared for . An internet search shows a plywood floor with lots of insulation under it . Are they prone to leaks which in turn would soak the insulation ? Is the hull viewable inside on these boats ? Just trying to cover my bases when I go to look at it . The only thing I can think of is to look for loose rivits or maybe cracks in the transom . I'll of course want to hear the motor run and inspect it for cylinder pressure . Anything else anyone can think of checking ? Thanks for any guidance .