Postby jss06 » Thu Dec 10, 2015 5:15 pm
The drag from a squared off rear is not bad. I averaged 21 MPG over 3000 miles round trip to Yellowstone last year. Your design is 1.5ft wider and about 2 feet longer than mine.
That's a good point, jss06. You can see that mine has a flat back and that it is just a few inches higher than the tow vehicle, which normally gets 19 mpg, hwy and 15 mpg, city. When towing, I get 15 mpg. The best check of that was on my 5,000 mile trip. Possibly the most important thing is to keep the trailer within the tow vehicle's lines/width. My cabin is 5' wide and 8.5' long. My tow vehicle is 5' wide. Keep the weight as low as you can, too. That will help.
According to your picture, your boat/kayak is going to hang over anyway; so, I doubt the flat back will make much difference. The boat/kayak will. Just adding a curved luggage box on top of my stepdaughter's minivan made a difference of 6mpg.