Don’t bet your life on questionable lifelines
Issue 69 : Nov/Dec 2009
The following is an excerpt from the second edition of Don Casey’s This Old Boat, published in April of this year by International Marine.
Most old boats have been delivered with lifelines rigged with coated wire. Coated wire is an astonishingly bad idea. Not only does the coating promote corrosion by depriving the stainless steel of essential oxygen, but by design the inevitable corrosion of the wire is hidden from view. The true strength of aging coated lifeline wire is a bad-odds gamble, with the ante being someone’s life. That is why they are called lifelines. Just for the record, the Offshore Racing Congress (ORC) bans coated lifelines.
Examine coated lifelines closely. As they age, the vinyl coating hardens and cracks, and soon enough rust appears at the cracks in the vinyl. This instantly condemns the wire — no ifs, ands, or buts. Likewise any kind of bump or lump in the vinyl covering means a tumor of corrosion inside. If you see rust stains anywhere on coated lifelines, even at the ends of the coating, put lifeline replacement at the top of your priority list. Falling overboard is far and away the most serious risk boaters face, and weak lifelines greatly increase your exposure. You are safer without lifelines.
I urge you not to replace old coated lifelines with new coated lifelines. The best wire for lifelines is Type 316 1 x 19 rigging wire. The same outside diameter will deliver more than three times the strength of coated wire, the 316 alloy will resist corrosion for a long time and, if any does occur, it will be immediately visible for evaluation. Given that safety at sea is surely more important than convenience at the dock, I also advocate abandoning gates in favor of a continuous lifeline from bow to stern. In my experience, gates are rarely in the right place anyway. They are like an open manhole in the dark if accidentally left open. They at least double the number of end fittings, thus doubling too the possibility of fitting failure, not to mention doubling the fitting cost. (If safety is your concern, you are paying more to get less.) And as an added benefit, a pair of boat-length runs of rigging wire can be a priceless onboard resource in the event of a rigging failure. On our boat, a ketch, the upper lifelines are the same wire as our main shrouds, and the lower lines are the same as the mizzen shrouds.
You have three options for end fittings. There are do-it-yourself hand-crimp terminals available that claim to deliver about 70 percent of the wire strength, but that is on 7 x 7 wire. I fear that the grip of these crimp fittings will have significantly less strength on the smoother surface of 1 x 19 wire. I have only anecdotal data to support this concern, but if you decide on the greater safety of uncoated wire, you should pair this with the greater strength of either machine-swaged or swageless terminals. You will need a rigging shop to install swaged terminals. Several manufacturers offer complete lines of swaged lifeline fittings, including integral pelican hooks, gate eyes, turnbuckles, and threaded adjusters. These make for very attractive lifeline installations and, because the swages live their lives horizontal, internal corrosion is less prevalent.
A do-it-yourself alternative is to terminate the lifelines with swageless terminals, typically fork or toggle jaws at the bow and studs or eyes at the stern joined to turnbuckles. You can lower the cost without much compromise of strength by eliminating the turnbuckles and substituting a multi-purchase lashing of high-modulus, small-diameter line to tension the lifeline and attach it to the stern rail. However, I prefer a turnbuckle because it allows tension to be eased and the clevis pin removed to drop the entire lifeline to deck level between any pair of stanchions, effectively giving you a wide and ideally located boarding or loading gate.
High-modulus (or hi-mod) lashings inevitably lead to the question, why not just replace the wire altogether with high-modulus rope? A 1/4-inch double-braid line with a polyester cover for abrasion and UV protection and a high-modulus (Dyneema) core can have a breaking strength exceeding 4,000 pounds, about twice as strong as coated lifeline wire of the same outside diameter. The rope is more expensive than the wire, but only modestly so, and it has the advantage of being much lighter and more comfortable. A thimbled eye splice at each end would be all the “terminals” required, with one end tensioned with a multipurchase lashing. Hi-mod rope lifelines would require you to learn to do a core-to-core splice. Beyond this intellectual demand, the other drawback is that there is no way to tell when or if the strength of the line has been degraded by exposure. I would caution against trusting rope lifelines more than five years old, based on the life of polyester halyards that have the longevity advantage of being vertical rather than horizontally exposed to the sun’s rays. By contrast, Type 316 lifelines should last two decades or more.
Don Casey became the authority on boat fix-it projects with This Old Boat. He is the author of a series of books in the International Marine Sailboat Library and of Dragged Aboard: A Cruising Guide for the Reluctant Mate. He and his wife, Olga, have been cruising aboard their 1969 Allied Seawind, Richard Corey, since 2002.
Thank you to Sailrite Enterprises, Inc., for providing free access to back issues of Good Old Boat through intellectual property rights. Sailrite.com
