I use the Round Turn and Two Half Hitches more frequently than any other knot. It’s perfect for fenders, and perfect for tying up the dinghy. Any time there is a load on the line, the round turn takes the load and you can finish it easily with the half hitches. I use a variation that I haven’t yet seen elsewhere, by making the second half hitch in the opposite direction of the first one. The result is a knot that is more compact and stable – meaning less likely to loosen itself up as the line gets worked, and that makes it more secure.