Larry Bunner had these, so I went on line and bought a couple of
eight foot versions myself:

I like wide straps so that they don't crush the glider. These are way stronger
than you need. I lashed two gliders down with 8' straps. They were both in heavy
water proof bags so it was a close fit. The eight foot strap works better on one
glider with plenty of extra strap.

The graphic is live.