One Knot - Three Names - Clove Hitch, Tow Half Hitches, Double Half Hitches.

It is called Clove Hitch, Tow Half Hitches, Double Half Hitches.
It is really the same knot that is used in slightly different situations.

Learn the basic shape, then you can improvise in the use of it in many different situations in life, on the boat, at outdoor, in home.

It is an incredibly strong and versatile knot.