Dave M I would never take out an equity loan on my house to buy a boat. I am just too conservative for that. The boat can stand on it's own or I wouldn't buy it.
You need no documentation to take the deduction. You simply need the amount of interest paid in 2002 and to whom it was paid. This goes on form A under additional interst paid. It is really no big deal.
But......definitly get the paperwork from the bank. Whether it is a 1098 or a statement or a letter, and put it in your files. I would also be prepared to justify the deduction with a description of the boat and the amenities. I did get audited once and these things came in very handy and I had no problems.
Taking any other deductions like customer trips etc. can be a little tricky depending on who owns the boat (company or personal) and how the company is set up (LLC, Sub S, C Corp, etc), It can also affect how the interest deduction is taken.
Talk to a knowledgeable accountant so you do not get into trouble.