How to Choose Dock Lines: Material, Size and Length

Dock lines do one job: keep the boat where you left it without wearing out the boat, the dock or themselves. Here's how to choose them.

Material: why nylon

Nylon stretches under load. That stretch absorbs the jerk from wakes, gusts and surge, which is easier on your cleats and on the line itself. That's why nylon is the usual choice for dock lines, while low-stretch fibers like polyester or UHMWPE are used where stretch is unwanted.

Construction: double braid vs. three-strand

Double braid (a braided core inside a braided cover) is smooth, soft in the hand, resists kinking and coils neatly.
Three-strand is typically less expensive, stretches more and is easy to splice yourself, but can kink and feels rougher.

Diameter

Bigger is not automatically better: a line must fit your cleats and fairleads, and a line that's too stiff for the boat's weight gives you less useful stretch. Check your cleat size and the builder's recommendations. If you're between sizes, ask us with your boat's make, model and cleat size.

Length

Bow and stern lines need to reach from your cleat to the dock hardware with enough tail to make off.
Spring lines run fore and aft along the dock and are usually the longest lines on the boat.
On a catamaran, wide beam and widely spaced cleats often mean longer lines than a monohull of the same length.

Eyes

A factory eye (ours are 30 cm, about 12 in) drops over a cleat or piling. Larger pilings may need a bigger eye or a bowline.

Protect them

Most dock lines fail from chafe, not overload. Add chafe protection wherever the line crosses a chock, fairlead or dock edge, and inspect regularly. See our guide to preventing chafe.