15 years surprises me. I mean, who finances a car for 15 years? I've never heard of that, and I assume a boat is similar to a car (used often, depreciates fast, needs constant maintenance, etc). I figured it was about 5 years max like a new car.
Learn something new everyday.
A car is used daily.. It is rare for someone to use a boat daily and place the same amount of wear and tear on it as a vehicle.