A roll of chain-link fence will do to get a semi on and off a beach, but its a bit much to haul around.
You might consider sections of fiberglass grating, which has a pretty huge surface area for anchoring, and can be made with a gritty grip surface.
I use 2"x2" grid 2" thick, and only flexes a little when I use it as a ramp for my 3-ton truck (48" x 16"). Not the cheapest or the lightest option out there, but super strong, durable and rust free. Look up industrial grating to find a supplier, some might have off-cuts for a reasonable price.
Careful how you mount them though, they will saw through any strap given the chance--better to bolt them on.