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VOL. 12 NO. 3
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Knots and lines

Discover the different types of rope and their uses

Knots and lines

A good marine knot should be easy to tie, easy to untie and hold fast under the conditions for which it’s intended. Knot tying is part of the practice of marlinespike seamanship, which is the general knowledge of knots and the care of rope. The term originates from a pointed metal tool, a marlinespike, used in working with rope.

When aboard a boat, a rope is generally called a line. There are three ways to tie a line:

  • Knot—a general term for securing a line to an object, another line or to itself. Specifically, a knot is tied in a single line.
  • Bend—a type of knot used to tie one line to another
  • Hitch—a type of knot used to secure a line to an object

Types of rope
The three most common types of synthetic rope used today are nylon, polyester and polypropylene. It’s important to buy the correct rope for the intended use.

Nylon rope is strong and has good resistance to chafing and rubbing. It can stretch considerably (up to 20 percent) without damage to its fibers. This shock-absorbing quality makes it ideal for anchor, mooring and dock lines. Nylon rope wears well, resists mildew and rot but doesn’t float. Three-strand nylon line is preferred for dock lines since it stretches enough to dampen the shock of wave action and wind against cleats.

Polyester rope is about 10 percent weaker than nylon rope of the same diameter. It stretches very little, which makes it suitable for halyards and other sailboat rigging, towing line, and other applications where you don’t want stretch to interfere. It chafes easily, so check it often, and use chafe protection as needed.

Polypropylene rope is light and costs less than the other synthetic ropes. It lacks the strength of the other two and is slippery, which increases the chance that a knot will fail. Polypropylene also deteriorates more rapidly in sunlight. Its fibers tend to fray and break, and it can break under high stress. However, polypropylene floats, which reduces the risk of the line wrapping around a propeller and makes it ideal for towing dinghies and water-skiers. It’s not good for dock lines because its hard surface tends to slip off cleats, and it can cause cuts if it runs free through your hands.

Every skipper needs to know how to tie a few basic knots, including the cleat hitch and bowline.

To learn to tie additional knots, take our Seamanship course.
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