I live onboard a 45 foot Morgan Ketch on the James River in Virginia with my wife, Suzanne. Recently, we had a summer visitor, a tropical storm named Hanna. According to forecasters, Hanna was supposed to be a hurricane that would blast right over us, leaving destruction and lots of water in her wake. Because of this, Suzanne and I had a series of discussions about dock lines, the sort with one person saying "are you sure we have enough?" and the other one saying, "Yes, I'm sure." Repeat as necessary until the storm is gone.

There is no fool–proof way to protect your boat from storms or careless boaters. In any storm, some boats will lead a charmed existence while owner who seemed to be doing everything right two slips down ends up an insurance casualty. However, as the old saying goes, fortune favors the prepared. The better your plan for docking, and the better your choice and care of dock lines, the more "fortunate" you will be.

FRANK MUMMERTA line thrown over one horn of a cleat might hold you in place for a temporary stop, but any significant water movement and the boat will quickly be adrift.

While it's easy to take dock lines for granted, a dismissive attitude is a prescription for late–night, bad weather disaster. Knowing how to appropriately connect boat to dock is vital for a good night's sleep when the wind is screaming through the rigging.

BUYING LINES

Dock lines come in two varieties – braided or plain laid. Braided line usually has two parts, an inner core for strength and an outer core for abrasion resistance and handling comfort. Plain laid line, on the other hand, is made up simply of individual lines, wrapped together for strength and resistance.

Braided line tends to be stronger, but has less elasticity and costs more. It should, however, last longer, since the outer cover can be constructed of materials that wear better. Double braid can be purchased in a variety of materials and weaves, allowing for more flexibility in choosing the "perfect" line.

Dock lines can be pre–made, with an eye loop installed in one end by the manufacturer, or you can make your own eye loops to the exact sizes you need for the dock you use. Although double braid can be worked by the average boater, it generally requires special tools and training. Meanwhile, plain laid line is much simpler to splice and work. The basic instructions can be found in "Chapman's Piloting and Seamanship," and the tools used can be nothing more than a pocket knife and a pencil to open up the line for tucking parts together.

FRANK MUMMERTThe bowline looped around this bollard will definitely keep the boat in place, but the other line is waiting for a chance to slip loose.

Any line needs to have the cut ends prepared to ensure that the line doesn't unravel. The simplest system, for synthetic lines, is to cut the line with a heated knife or to seal the end with a hot soldiering iron or lighter. This makes a good seal in an emergency, but long term sealing – called "whipping" – requires more effort.

Cheap solutions can be had wrapping the bitter end with electrical tape or by dipping it in liquid glue, sold as "instant whipping" in marine chandleries. But true whipping is created by wrapping the end of the line with marline or whipping twine around the end to protect it against fraying. While whipping lines requires more effort, the results can be strong and salty looking – and you can do it in winter. (For a story on how to whip your lines, see link).

For any line that will be a permanent dockline, one end should have an eye splice. The act of tying a knot in a line weakens it and a line that will undergo the constant pull and release of a floating boat tied to a solid dock will work grit into the fibers and cut the line internally. Any tight bend in the line can weaken it by up to 15 percent, and a small complete circle, such as those used in a cleat hitch, clove hitch or bowline, will reduce line working strength by at least 30 percent. According to the US Coast Guard's Small Boat Seamanship Manual, a well–made eye splice reduces the line's breaking strength by only 5 percent.

There is no hard and fast rule for how big a line should be for a given boat, but experts agree that a good rule of thumb is 1/8 inch of diameter for every 8 to 9 feet of boat. For example, a 27–foot sailboat would take a 3/8–inch line. A 45–foot trawler would take 5/8–inch line. In terms of length, many recommend a matched set of lines – all the same length – and each as long as the boat. (For a story on sizing, see link.)