How to Choose Ropes and Wires for Boat Rigging

We've come a long way since sailboats plied the world's waters with rigging and lines made from hemp lines in varying diameters. Early spring is the perfect time of year to inspect your boat's wires and lines, replacing what is worn.

Difficulty: Moderate

Instructions

1. Know these wire basics. The most commonly used wire on a recreational sail boat is 1x19 stainless steel wire. The first number represents the number of strands in each wire, the second is the number of individual wires. So a 1x19 is 19 individual strands making up a single wire. It's stiff and best used for the standing rigging, shrouds and stays. For more flexible wire, choose 7x19 stainless steel wire. It's flexible enough to be used in the running rigging like halyards, or in steering mechanisms.

2. Avoid galvanized wire. It is less expensive than stainless steel, but it's weaker and stretches more. When the galvanizing inevitably wears off, your wire will rust.

3. Know when to replace wire. It's time to change your wire when you see rust between the strands or breakage of individual strands. A single break here and there is OK. Be sure to clip the strand breakage near the wire surface so the hook that is formed doesn't snag a sail or person. If you notice 2 or three on the same wire, it's time to replace. Wires go bad with little notice. Since they are used in halyards, stays and shrouds, if one suddenly parts, it would be a much bigger problem than losing a jib sheet. Replace worn wire with that of the same length swaged by professional riggers. Wire's biggest advantage over rope is its strength, 25% stronger than nylon, 35% stronger than Dacron.

4. Understand these rope essentials. Rope has inherent tensile strength depending on the material used, which can be Manila hemp, sisal, cotton, nylon, Dacron, nylon or polypropylene. Most rope used on a boat is braided with a core of three strands inside a soft cover. Laid rope is braided with the strands exposed. It is more resistant to abrasion than laid rope and should be used for halyards. Laid rope can be readily spliced, producing a loop much stronger than that from a knot. Each material has different advantages. The anchor rode and mooring lines should stretch to absorb strain, so nylon is a good choice. You don't want to use nylon for a sheet or halyard because you'll be constantly adjusting the sails. Dacron is better choice here. Dacron is easier to handle, but it isn't as strong as nylon, so you'll need a thicker diameter for the same holding power. Neither material is buoyant, so be careful that it doesn't sink. Polypropylene does float which makes it a better choice for ring buoys or dingy painters, especially if one is tied up to the stern near your propeller. You don't want a line to foul a prop there. When a rope is used for a specific purpose, as on a boat, it becomes a line. Choose the thickness of your line based on its intended use and your anticipated loads. Replace rope when it becomes frayed.

5. Grasp how much rope to buy. For a halyard, add the mast height to the length of the headstay plus the distance to the winch with 10 feet for tail. For your working jib's sheet, buy just more than the length of your boat. A Genoa's sheet should be one and half times the length of your boat. Mainsheets vary greatly in how they are rigged, so when it comes time to replace it, simply undo and measure it.