How easy it will be to transport the canoe on top of a trailer, will depend upon the physical shape of the canoe's gunnels. If the canoe has a relatively flat sheer line, where the bow and transome are not raised much higher than the center line, you will have little difficulty. However, if the bow and stern are significantly higher than the mid ship depth, you will need to construct a rack of sorts to support the center part of the hull. The boat should be transported bottom side up for the best aerodynamics.

If the sheer line is flat, the foam blocks and ratchet straps will work quite well. If it is not, the center of the canoe will not touch the trailer and will be supported by the bow and stern, which is inheritantly unstable. Cross bar rack supports that are the thickness of the open space or even slightly higher, can be affixed to the boat with straps. The whole lot can then be strapped to the top of the trailer.

To lower the drag and buffeting when in motion, you will want the boat to be as low to the trailer's surface as possible, and as perfectly aligned fore and aft as feasable. You will also want to install two bow lines in a V shape, going from the bow ring to each front corner of the trailer. This will help maintain the alignment of the boat whilst in motion, and prevent it from slipping rearward under the straps when travelling. Two cross straps, and the two bow ropes are sufficient to hold the boat into place at highway speeds.