I have financed all my boats on a 15 year loan because it gives me the lowest possible payment. Then I make double or triple the minimum payment every month. I had my last boat for 4 years and only had about 2 years left to pay on it when I sold it on a 15 year loan.
My logic is that in the event that something happened and I lost my job, I am far enough ahead after a year that I could skip a couple years of payments if I needed to. With good credit and a fairly low interest rate, it is pretty cheap money to borrow.
Of course, my logic is mine, and will make no sense to some, but it works for me.
Some people use the logic of saving up enough to pay cash. It is what they are comfortable with, but in the 6 years they were saving to pay cash, I had a boat for those 6 years and have it paid for.
In the end, you end up in the same place.