Start with the transom. From inside the boat find the lowest part of the transom that you can access. Use a 3/8" drill bit and use tape to mark the 1" depth mark. Drill into the transom at the low point and about 4" apart..3-4 holes 1" deep check the shavings. If they're light in color and don't have any moisture then more than likely it's OK. If dark colored and damp...Transom is wet and will eventually rot. If you have access to the stringers (i.e. via the ski locker or other hatches) drill them as well. If all is A-OK then fill the holes with some 3m-4200 caulking and go have fun. If NOT, then start reading on this forum about Transom, Deck and Stringer restoration. There Are LOTS of em.