Wire rope used for standing rigging on boats is usually 1 x 19 stainless steel, which means that it has one strand containing 19 wires. If conventionally stranded, all strands are round and identical. Branded Dyform wire rope has strands of varying diameter that are not round. It has a smoother surface and is 30% stronger but costs half again as much. Galvanized wire rope is perfectly acceptable for shrouds although not for the forestay of a hanked-on jib. It has the advantage of showing early signs of impending failure, which stainless steel might not show, and it is significantly less expensive.
The end of a wire rope terminates in a loop or a fitting. If there is a loop, it should encircle a metal thimble to protect the rope from chafe. The end can be clamped, crimped, or swaged back onto the standing part. Galvanized wire rope can only be clamped. Cable clamps have a saddle and a U-shaped rod that bolts into the saddle at two points. They must be installed with the saddle against the standing part, not the bitter end. (“Never saddle a dead horse.”)
Swaged
fittingsSwaged fittings are crimped on in a shop by trained riggers using special presses. If over-compressed, they are prone to failure. They also provide a likely entry point for corrosion if not protected from the weather. Swageless fittings can be installed onboard the boat with common hand tools and
fittings are just as strong as swaged fittings. They cost about twice as much as swaged fittings and are therefore not significantly more economical for do-it-yourselfers, especially if you make mistakes. Swageless fittings Two- or 3-piece swageless fittings (eg, Norseman and Sta-Loc) have a body that slips over the wire rope. You unlay the outer strands, fit a cone or wedge over the inner strands, and re-lay the outer strands over that fitting, easing the strand ends into a former, or head fitting, which then screws down onto the body. Tape the wire rope and use a cutting block to ensure square ends. Use a bit of grease on the threads. Hand- tighten slowly, backing off frequently to ensure that wire strands are forming properly over the cone or wedge. Turn only the top fitting on right- hand laid wire rope or only the bottom fitting on left-hand laid. Lastly, back off, remove the grease, apply plain Loctite or 3M 4200, and tighten snugly. A single-piece swageless fitting called Quick Attach eliminates the cone or wedge and can be installed in about one minute.