When was the last time you went carefully over every detail of your boat’s rig? The chances are good that it may have been a few years, and it’s possible that you may never have looked at it in the detail it deserves.
Take a good look at the spreader ends in the accompanying photograph. These are tubular aluminum spreaders, with cast aluminum plug inserts as end fittings. This is a fairly common spreader configuration on boats under 35 feet, particularly boats built in the 1970s. The problems, however, are not unique to this arrangement; neglect is the worst enemy of anything associated with a boat, and the rig is no exception. The end fittings shown are from the mizzen spreaders of a Gallant 53, a heavy duty cruising boat built in England. As is the practice in many areas, the rig had not been unstepped in several years, and previously when the rig was removed, the spreader ends were left padded and taped-another common practice.
In fact, it had apparently been more than 10 years since the spreaders were seized and taped. After all, how frequently do you bother removing spreader boots and taping to check the condition of the spreaders and rigging?
No matter how well the spreader ends are protected, and whether you use ready-made vinyl spreader boots or conventional rigging tape, water will get through to the fittings inside. On a boat used in saltwater, the corrosive nature of the atmosphere can cause rapid disintegration of aluminum fittings (never mind the fact that the spreaders might be 25 feet or more off the water). The thorough taping job you did on the spreader ends may actually accelerate the problem by holding in water.
The problem can be just as bad on a boat with wooden spreaders. Wooden spreaders are usually spruce, a wood with very low resistance to rot. Water trapped by spreader boots, or the taping of the inboard ends of the spreaders at the mast fittings, can rot a spruce spreader in a season. Keeping wood spreaders varnished, while it can help, is no guarantee of protection. Wooden spreaders are almost always fitted with metal ends, both at the mast and at the outboard end of the spreader. If these fittings were not thoroughly bedded with compound when the spreader was assembled, all the varnish in the world won’t keep water out of the joint between the spreader and the metal end fitting. And water sitting in this joint will eventually cause the spreader to rot.
If the boat is decommissioned some timeduring the year, that’s the time to make a careful inspection of the rig and rigging. Every component must be gone over thoroughly.
First, check the mast tube itself for problems. Do the masthead sheaves turn freely? Are the edges of the sheaves worn, so that a halyard might jump the sheave and wedge itself between the sheave and its box? Is the mast dimpled, or bent?
Worn sheaves should be replaced. Stainless steel wire tends to chew aluminum sheaves over time, particularly those used for spinnaker halyards. Sheaves that show only slight wear or burrs should be dressed smooth with a file.
There should be no sideways play in halyard sheaves. Space between the sheave and the sheave box can be eliminated with micarta shims, which will also help prevent the sheaves from seizing. Seized shims can usually be freed with liberal applications of WD-40 and heat applied with a propane torch.
Physical damage to the mast tube in the form of dimpling, wrinkling, or bending requires professional analysis by a spar maker. This type of damage rarely happens when the mast is in the boat. It is more likely to result from a shipping accident, or from stepping or unstepping the mast. A mast can become permanently bent through improper blocking during storage, however.
Look for grooves in the mast extrusion where internal halyards exit the mast. Check the mast heel for corrosion. Corrosion at the heel of the mast is probably the most common problem with keel-stepped aluminum spars. The cure is to keep the area of the mast step in the bilge bone dry, and provide drain holes in the mast heel and mast step. Deck-stepped spars are not immune to heel corrosion, and also require drain holes in both the heel and the step.
Examine all mast fittings, winches, and cleats for signs of corrosion between the fitting and the mast. Unless the fittings are bedded, there’s a good chance of serious pitting here. The first clue is likely to be a powdery white deposit around the edge of the fitting. All fittings on the mast should be bedded, using either zinc chromate paste or plastic shims.
Check all the rigging tangs on the mast. Look particularly for elongated clevis pin holes or cracks radiating from clevis pin holes or points of attachment to the mast tube. Any damage to tangs is unacceptable. Elongation or cracking means the metal of the tang is too thin for the load, or there is simply not enough metal between the clevis hole and the edges or end of the fitting.
Brownish discoloration on tangs should be polished out using a stainless steel cleaner or buffing pad to make examination easier, Don’t use sandpaper or a harsh abrasive. You may destroy the surface polish of the stainless steel, which is its major source of discoloration protection.
Badly discolored wire or fittings should probably be discarded. Any wire having a sharp kink in it should be replaced. Any swage fitting that is cracked should be replaced, although the lack of cracking is not necessarily an indication of health.
Stress corrosion cracking can be a serious problem with stainless steels other than type 316 on boats kept in saltwater and warm climates. The greatest danger from stress corrosion is that a stressed fitting usually appears to be in perfect condition prior to failure. Many mysterious rigging failures (“I dunno, it just broke”) are no doubt due to this little known and often misunderstood problem. There is evidence, however, that keeping rigging clean and polished with a product containing lanolin or silicone can decrease the possibility of a failure due to stress corrosion cracking.
Carefully examine each strand of rigging wire, including terminals, toggles, turnbuckles, clevis and cotter pins. Last season I saw a very expensive rig which went by the boards because a bolt was “temporarily” inserted in place of a missing clevis pin, Unfortunately, it was taped up and forgotten before anyone got around to replacing it, and it eventually wore through.
Any swage fittings having a ‘banana shank” should be replaced. (A banana shank is a curved shank that results from passing the fitting through the swaging machine without using the proper guide.) Likewise, retireany cracked or bent turnbuckles or toggles. Seized turnbuckles should be freed using a penetrating oil such as WD-40, and heat from a propane torch. Brute force is almost guaranteed to ruin turnbuckles with screws under 3/8 inch.
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