Dear Boat Doctor,
The lifelines on my J/35 are getting a little tired and need replacing. With all the options now, I'm having a hard time deciding what to replace them with. I like white covered lifelines but the plastic seems to crack pretty quickly.

Charlie Wiesman
Grosse Point Farms, Michigan

Dear Charlie,

Every lifeline option has pros and cons. White PVC covered lifelines are the traditional favorite since at least the 1970s. Although they look nice and don't bite skin too hard, they do have some shortcomings. Over time the plastic cover breaks down and allows water inside it, which corrodes the wire. You'll often see cracked plastic and rust staining around cracked plastic and at the terminals. This is a sign that your lifelines need replacement.

If you choose to go with white lifelines, get a brand of wire with a thick coating and make the overall lifeline as large as you can. The actual wire inside a lifeline can be much smaller than the cover.

A better choice may be uncovered lifeline wire. Standard 1x19 wire is the best choice. This is the same type of wire used for your shrouds. You can size the wire up since there is no cover taking up space and there is nothing to trap water. Using this option, the wire and terminals tend to be larger, so the cost goes up. This is by far the strongest most durable option and I think it is the best looking.

The newest option is a fiber lifeline using spliced Dyneema cordage. I recommend 5-millimeter Hampijian Dynex Dux, which is a heated Dyneema rope from the commercial fishing industry. This material is rope but it is light and behaves a lot like wire in that it is low stretch, very strong and incredibly light. The lifelines are hand-spliced on the boat. If you learn how to splice this material-it's easy-you'll find lots of applications aboard your boat.

Dux is comfortable to hike against, very durable and nicer than covered wire. It won't corrode and fatigue, but it will chafe. Although the material will degrade on the surface in the presence of ultraviolet light, the degraded surface becomes protection for the rest of the rope.

The 5mm Dux is equivalent in strength to 3/16-inch 1x19 and about two or three times stronger than typical covered lifeline wire. This means that even if you chafe the lifeline halfway through the material is still as strong as the wire that it replaced.

The cost of this option is by far the lowest, especially if you learn to splice it yourself.