We regularly see dinghies secured to decks or davits with a variety of tie-down methods, some are tidy and solid, others maybe a bit more "freestyle" in their technique. It is important to keep the dinghy held firmly so that it stays in place in rougher sea conditions.
I have always liked to use ratchet straps when securing a load in my truck or on a trailer, but these are generally made of mild steel and susceptible to rust in the marine environment. Suncor to the rescue!
They have a full line of stainless ratchet straps in 1-inch, 1.5 & 2-inch widths and a variety of lengths.
Sold by Fisheries Supply: Click here.