I have straps on my hatches, but I had the holes already for latches. I took the L shaped latch parts off, but you could leave them on if you want. I bought a cheap set of 4 cargo ratchet straps from Harbor Fright come with about ten feet of strap on the non ratchet piece. I burned holes with a heated nail in the end a 16 inch segment and bolted it to the bolt that holds the "L" through those holes. Took the loop through the latch hole and that was it.
I did "invent" a different method. I cut a loop and passed it through the ring on top of the latch. After I heat sealed the end, I overlapped the ends about 3/4 inch and saturated the overlap area with Super Glue. I then put a piece of hard flat plastic on each side and clamped it together with vise grips. After it dried I cannot pull it apart SO FAR.
This could be a permanent way to fasten strap segments under minor loads. I bought the straps because I liked the colors, and at about $10.00 it was inexpensive.