This may be a dumb question, but it would be even dumber if I didn't ask it. i am looking for a used trailer for my 26' Wellcraft. i understand I need to make sure the weight rating is enough, but i have found a bunch that will carry the weight, but don't look long enough. what should the length be from the winch post to the end of the bunk/roller? i have been told to measure the water line, is that right?