A semi-trailer includes first and second main beams and left and right side rails. A cargo platform extends between the left and right side rails. Each of the side rails includes an aluminum extrusion including an upper portion including a platform engaging portion, and a lower portion including a winch track. The lower portion further includes a projecting hook engagement wall. The hook engagement wall includes an upper surface oriented toward the cargo supporting platform and an opposite lower surface. The hook engagement wall includes a tapered nose including first and second nose walls that define a nose angle X such that said tapered nose is adapted to be received in an open recess of an associated cargo strap hook that defines a hook recess angle X′.