Having a sailboat means that you have to know your knots. For me, it’s the simplest ones that give me trouble, like the dumb clove hitch.
I’ve had an entry about knots before, with cool videos, but the number of knots where limited. Then my friend Ron Purvis sent me this site: Animated knots by Grog. It’s much more complete, and he’s divided the knots by type: boating, fishing, climbing, etc. The pictures are also animated, and you can go picture by picture or streamed. There’s even a section on rope care. An excellent reference site, even for the seasoned knotters.