Several subscribers who read my recent blog post regarding stainless steel corrosion, “Detecting and Dealing with Stainless Steel Corrosion” asked if we had any guidance for someone who wanted to do a preliminary survey of their own rig, or the rig on a boat they would like to purchase. First of all, there is no substitute for a professional inspection. A good rigger has seen it all, and will recognize problems that the layperson will not.
For an offshore cruising boat, Practical Sailor would recommend a routine survey of the rig by a professional at every three-to-five years, or anytime trouble pops up. A good surveyor will walk you through the potential trouble spots, and a confident cruiser will be able to carry out the subsequent surveys on his own. Be pro-active and conservative. What appears to be minor corrosion can be a sign of more serious weaknesses.
The following DIY survey described by PS contributor and surveyor Frank Lanier should, as much as possible, be conducted at least once a year and before every long passage. If you have an older boat with known trouble spots like hidden chainplate corrosion, set aside time during the off-season to probe deeper.
Most sailors immediately think wire when they hear the term standing rigging, but that’s only one part of the story. Your pre-survey inspection should encompass several different components, from chainplates and turnbuckles to cotter pins and terminal ends. Here are three primary standing rigging components along with possible issues to watch out for.
Broken yarns or strands (aka fishhooks) are a clear indication that rigging wire is nearing the end of its service life, even if the other strands appear good. You can check for broken strands by wrapping toilet paper around the wire and carefully running it up and down while looking for snags or shredding of the paper.
Nicks and scratches that affect multiple strands or one strand deeply should also be noted as possible cause for replacement, as should kinks, flat spots, proud strands and corrosion, particularly where the wire enters a swage fitting.
Floppy shrouds or stays should also be inspected to determine the cause of the looseness, which can indicate anything from a much needed rig tune-up to a failed mast step.
Of the various wire terminal fittings found on sailboats, swage fittings are the most common source of terminal failures.
Each should be checked carefully for signs of fatigue, proud strands (a common indication of broken strands in the swage), cracks, and corrosion. A small, handheld magnifying glass can be very helpful during this inspection. Pay close attention to lower terminals, which are particularly susceptible to corrosion as a result of salt-laden water running down the wire and inside the fitting.
Bent or banana-shaped fittings (the result of improper compression of the fitting onto the wire) are also items of concern that will need to be addressed.
Chainplates should be checked carefully for issues such as movement, rust, cracks, deformation of the clevis pin hole, and improper lead angle. Chainplates that penetrate the deck will often leak (due to movement and/or caulking failure), and the damage this causes, both to the interior of the vessel and the chainplate itself, can be significant.
Where chainplates are bolted to a bulkhead or other interior structure, look for discoloration, delamination, and rot due to water intrusion. Chainplates can also be compromised due to crevice corrosion, even though the metal above and below the deck appears to be in excellent condition. Crevice corrosion occurs when stainless steel is continually exposed to stagnant, anaerobic water, such as that found in a saturated wood or cored deck. This is one reason why chainplates that are glassed in or otherwise inaccessible for routine inspection are undesirable.
While the life expectancy of wire rigging is determined by a myriad of factors (where the vessel is located, type of stainless, amount of use, etc.), the general rule of thumb is that it should be replaced every eight to 10 years, sooner if extenuating circumstances such as offshore passages, extended cruising, racing, etc, are in the mix. While an owner may offer assurances or hazy recollections of rigging replacement, unless these improvements are properly documented, the best policy is to assume the rigging is original and plan your purchase strategy accordingly.
For more on rig inspection see my previous blog post “What’s Hiding in Your Rig?” Informed by the wisdom of expert rigger Brion Toss, the post contains multiple links to related Practical Sailor reports.
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