Outboard mount

Wonder the best way to make a outboard mount in the box of my truck. I travel rough roads and don't want it flying around the back. Show me your ideas!. My motor is a 6 hp

 

Why not build a box and line it with horse mats or some sort of padding?

 

I use an old piece of carpet and straps, transporting a 2hp, 5 hp and 15 hp four stroke. No issues, just don’t get lazy and think 1 strap is enough. I like the crate and horse-mat idea...