I use noodles with shock cord through the middle (hook on one end, loop on the other) strapped to which ever end of the boat is on the beach. These are big noodles (4" or so in diameter) not the regular sized pool noodles. Another options I've used when I had to improvise is throwable boat cushions with a bungie hooked to the straps. You should be able to improvise something with shock cord and some kind of hunk of foam that is portable and does what you need. One advantage of noodles is that you can stuff them in your hulls via the deck ports and take them with you so they don't get "borrowed" and they are with the boat when you land.