According to Chapman Piloting, Seamanship & Small Boat Handling, rope is considered “line” the minute it’s put to use on a boat. The most common ropes made for boating are now constructed of nylon. The elasticity allows it to absorb shock, such as when a boat rises at anchor in steep seas. You should also know something about:
How They’re Made
Ropes are made from fibers, twisted into yarns and grouped into strands. Those strands are then twisted or braided to form rope. As its name implies, “three-strand” rope is made from triple strands, most commonly twisted together in a clockwise pattern known as a “right-hand lay.” Opposing twists within the strands and fibers prevent the rope from unraveling. Double-braided line features a braided core surrounded by a braided cover.
How They’re Used
Braided construction is preferred for lines that will be frequently handled, like dock lines. Because individual strands are quite small, braided line is soft, very flexible and highly resistant to kinks. Three strand rope is typically cheaper and more resistant to abrasion, but it’s rougher to handle. That makes it a good choice in workhorse applications, such as the anchor rode.
How To Make Them Last
Keep ropes clean with the occasional wash. If you put one into a pillowcase or mesh bag, you can throw it right in the washing machine. Soften stiff ropes in a solution of fresh water and fabric softener. Let them sit in it overnight, then rinse thoroughly, and dry away from direct sunlight. Prevent abrasion and wear with chafing protection, such as leather or plastic tubing, on any location where a line may rub on a dock, gunwale or hawse pipe.
As a general rule, size bow and stern lines to about two-thirds of the boat’s overall length. Match spring lines to the overall length. Line diameter also relates to the boat’s length:
Size of Boat - Line Diameter
Under 20' - 3/8"
20' to 30' - 1/2"
30' to 40' - 5/8"
40' to 60' - 3/4"