When I tow my Triton Bass Boat with cover on behind my '98 Expedition, the draft over the top of the truck flows down on to the boat cover and often causes the rear corner of the cover to pull off the boat. I am looking for some aerodynamic device to attach to the truck to divert the draft over the boat. Anyone have an idea. I know I have seen them, but do not know what they are called to even search for them.