Re: prepare for sandy! knot tying class..
Yeah we often use the ole truckers hitch knot (do a you tube search) but that works best when you have two static points and is a bit more difficult to do when tying what is, in effect, a loop where there is no stationary object to keep it from sliding around what you are trying to secure.I have done what you describe a few times but for an application like that I much prefer a small ratchet strap.
"Ve are too soon olt und too late schmart."- A nameless German philosopher