"Fuel economy while not towing boat, 30mpg highway
doing 60 mph with boat, 20 mpg
doing 65 with boat, 15 mpg
Kinda weird that it drops so fast going justa little faster. It's got to be the additional wind resistance. "
That is dramatic. I'd be curious to see what improvement a cover over the boat would make. If you are pulling it any distance the cover may quickly pay for itself.