Of Interest to Captains (October 2017)


by Brian Brown

That old expression…an ounce of protection is worth a pound of cure is absolutely true.  However in the case of your boat’s lines you better ante up up:  An ounce of prevention is worth a ton of cure; your lines could be tasked to hold a ton of weight in a millisecond.  A worn or old line could be life threatening to you, your family and friends.  Its one thing to be docked, another when you’re rolling in ten foot seas and a frayed line splits and something comes loose.

Most people take ropes for granted—did I say that?—errrr…you’d better call them LINES if you’re crew on a boat.  (Don’t ever say ropes or a boater will know you’re a newbie.)  Lines do everything from keep your boat docked to hoisting your sails, rescuing a crew member and more.  To many people lines are replaceable and frequently overlooked…needing not to be looked after properly.  The use of lines—worn or until they break–is a common practice.  For safety’s sake, it’s better to regularly inspect, maintain and replace lines.

Let’s talk about reconditioning and line maintenance first.  Keeping your lines clean and salt water free will extend their life.  OK, so you say that’s impossible when you’re blue boating in the ocean, but just an hour or so spent maintaining your lines will change your mind.

Here’s a great trick for helping maintain lines…wash them in your washing machine.  Use normal laundry detergent but also throw in liquid fabric softener.  Yes…you’ll find that fabric softener—which is liquid wax—will soften the “feel” of the lines almost returning them to their “original” soft and pliable condition.   Next you’re probably asking…”won’t the wax allow for slippage?”  The answer is no.  Try it Mikee, you’ll like it!  You won’t believe the feel of the “hand” returns to your lines…it will be like, wow, they went from stiff and old to feeling almost brand new.  And for you laundry fanatics, please don’t put them in the dryer.

When you can, keep your lines inside and out of the sun.  In most cases both salt water and the sun will break down your lines (it’s a chemical reaction).  After every outing its best to hose down your lines inspecting them for fraying.

Next, let’s talk about dock lines and address chaffing…not the underware type.  Every boat in “resting” mode has to have some sort of line to keep it in position.  Whether that’s at a dock or on a mooring, these applications demand different types of lines.

When your boat is away from its regular slip or mooring, you need to have some designated nylon lines aboard, preferably with spliced eyes, ready for use when you tie up somewhere. We call these transient dock lines.  The eye in the end is easily passed around a cleat or piling by someone on the dock and the bitter end is adjusted on board. There are dozens of combinations of diameters and lengths.

Permanent dock lines are also made of nylon, but differ from transient dock lines in several ways.  First, they must be protected from chafe, the enemy of all lines in constant use. This calls for leather, rubber or fabric chafe gear where the line passes through the chocks, and possibly a chafe sleeve on the eye where it goes around the cleat on deck.  At the dock, lines should be protected from chafe using eye splices and shackles if the dock has rings, or eye splices and short lengths of chain if the dock has cleats.  Permanent dock lines should be cut to fit the particular boat in the slip.

Dock lines should be made from nylon, a synthetic fiber that has a superior combination of strength and stretch.  Nylon is strong (although it shrinks and loses about 10-15% of its strength when wet), durable, and stretchy (three-strand nylon stretches up to 16% of its length when loaded to 15% of its breaking strength), so it absorbs shocks.  Low-stretch lines, like old worn-out polyester double braid used for sailboat running rigging, are less desirable because they transmit shocks from waves, loading up and loosening dock cleats and your boat’s deck hardware. There are three main types of rope construction for dock lines:   three-strand, double braid and Mega Braid.

Three-strand line has a knobby finish, is easy to splice and is the most affordable.  Double braid is somewhat stronger for a given size, has about half of three-strand’s stretch, and is available in many colors so you can color-coordinate your dock lines to match the color of your trim or canvas.

Mega Braid is a 12-strand single braid.  Single braids are very supple and limp, so they are easy to coil and handle.  Mega Braid is frequently the choice for boats above 70′ and it’s harder to splice.

Many boaters will want lines which match their canvas work, or trim color.   Double braided dock lines are available in six colors plus white and white/gold.  Its recommended that 1/8″ of line diameter for every nine feet of boat length.  Larger lines will wear longer but stretch less.

Boat Length
Up to 27′ use 3/8″
28′ to 31′ use 7/16″
32′-36′ use ½”
37′-45′ use 5/8″
46′-54′ use ¾”
55′-63′ use 7/8″
64′-72′ use 1″ or more

Last, transient dock lines should be about 2/3 of the boat’s length when used on the bow and stern.  Spring lines should be equal to your boat’s length.