And yet another:
http://boatingsailing.suite101.com/a...oats_and_piers
Found this in the text:
Adequate Number of Lines - A properly secured vessel will be held by a minimum of four lines, a bow line, two spring lines fore and aft, and a stern line. Spring lines run from the fore and aft ends of the boat to a cleat or bullrail on the float. Picture tying a line to a fitting at the bow of the boat and running it back to a point on the float near the stern of your vessel. Having two spring lines running in opposite directions prevents your boat from moving forward or backward. Lines at the bow and stern prevent the ends of the boat from swinging out away from the dock.