Sailboat standing rigging takes an endless beating, but regular inspections and maintenance can head off failure.
Photo, Getty Images/MBBIRDY
Of all the systems I inspect when surveying a sailboat, none better embodies the “as strong as its weakest link” adage than the standing rigging. Although one of most crucial systems aboard, the lack of attention and maintenance it receives from most owners is almost criminal. Here’s how to ensure your “standing” rigging stays that way.
What Is It, And What Does It Do?
Standing rigging (stainless steel shrouds and stays) keeps the mast upright while transferring the forces from the mast and sails to the hull via the chainplates. Shrouds are the wire cables (or rods in some cases) supporting the mast from the sides (lateral support), while stays are the wire cables supporting it fore and aft (such as the forestay and backstay). Chainplates, the metal plates or rods bolted to the hull, deck, or a bulkhead, are the attachment points for the standing rigging, the crucial link between the standing rigging and the vessel’s structure. If the standing rigging is inspected, so too should these other components, as failure of any can result in dismasting.
Rigging is subject to extremely high loads, and a failure can be disastrous. Photo, Frank Lanier
Stainless Steel 101
Most all production sailboats use stainless steel standing rigging, normally 1 x 19 stainless wire (the focus of this article) or to a lesser extent, rod rigging. Chainplates and other fittings will also typically be constructed from stainless steel. While stainless steel works remarkably well, it has one significant enemy: corrosion.
Stainless steel generally lives up to its name, assuming that the correct grade or series is chosen for the job and that it is installed and maintained correctly. Type 304 is a good, basic, multipurpose stainless steel for general marine use. Add a bit more nickel content and molybdenum to the mix and you get types 316 and 316L, both of which have improved resistance to corrosion. Type 316L features a lower carbon content to prevent carbide precipitation (and intergranular corrosion) when welded.
From a boat owner’s perspective, all these types of stainless have one big thing in common – a self-generated protective coating that helps prevent corrosion. The chromium used in stainless steel combines with oxygen to form an invisible layer of chromium oxide, which protects and prevents corrosion from penetrating into the stainless. This inert film is also self-repairing, as long as sufficient oxygen is present.
Stainless steel is much more prone to corrosion when installed in an anaerobic (no oxygen) environment. A perfect example of this is chainplate failure where it transitions through a deck.
The horizontal surfaces on most boats (e.g., decks, cabin tops) are of “cored” construction, meaning some material (e.g., plywood, end-grain balsa, foam) is sandwiched between an inner and outer layer of fiberglass. The downside to cored construction is that any penetration into a cored area can allow moisture entry if the coring is not properly sealed during installation and the caulking used to seal the hardware fails. Once this occurs, the coring absorbs this moisture, holding it like a wet sponge against the stainless-steel chainplate.
That’s when it gets ugly. Over time, the oxygen in the water is depleted and the protective chromium oxide film breaks down, unable to renew itself. At this point, the iron in the stainless steel starts to deteriorate, resulting in corrosion and failure, despite the chainplate looking pristine above and below the deck penetration.
Additionally, stainless steel rigging that is older or has been exposed to heavy cyclical loading can develop fractures or stress cracks, which can lead to crevice corrosion and failure.
Standing Rigging Inspections
Standing rigging should be inspected at least annually, with some components warranting monthly checks during heavy use. This is especially true for rigging that is more than 10 years old, the generally accepted service life for wire rigging and recommended time frame to pull and inspect chainplates. This annual inspection is also a perfect time to have the rig properly tuned, another crucial aspect of standing rigging maintenance.
The easiest way to inspect your standing rigging is in the boatyard with the mast unstepped (removed from the vessel) and resting on sawhorses or similarly supported. This not only allows you to inspect the standing rigging but additionally provides access to fully inspect the mast and associated fittings. It also makes it easier to remove and inspect chainplates (if due).
If the mast isn’t unstepped, the next best thing is having a qualified marine rigger go aloft to inspect the rigging. Even with the mast stepped and no rigger, an inspection from the deck (eye level down) can be of great benefit. While it doesn’t replace going aloft, a good pair of binoculars can also be helpful when inspecting the mast from deck level.
1.These chainplates were glassed into the hull and corroded out of sight in an oxygen-deprived environment. 2. Unlike the example shown here, the legs of a cotter pin must be spread apart to keep it from falling out. 3. The best way to inspect your mast and standing rigging is with the mast unstepped. 4. This deteriorated mast step highlights the corrosive environment of your boat’s bilge. Photos, Frank Lanier
Speaking Of The Mast …
Any article on standing rigging inspections would be remiss without mentioning inspection of the mast itself. When surveying a sailboat’s spars and rigging, I start with a general overview of how everything looks. Are there any obvious issues? Is the mast “in column” (straight and centered when viewed from fore and aft, and side to side)?
Do the spreaders (which hold the shrouds away from the mast) bisect the shrouds at equal angles? Are the shrouds wired in place? Are spreader ends protected with rubber boots or tape? Are shrouds and stays free from kinks or sharp bends (which can cause deformation and hard spots in the wire) and correctly tuned?
Verify that all shackle screw pins are moused (secured) against unscrewing and that all clevis pins are secured with properly sized cotter pins. Cotter pins should fit snugly into the hole of a clevis pin and be no longer than 11/2 times the diameter of the clevis pin with the legs spread out 25 to 30 degrees to keep it in place. Don’t be afraid to cut the cotter pin legs if they’re too long, and please don’t curl them back like a ram’s horn, as it makes them difficult to remove in an emergency. Avoid taping cotter pins (as it prevents inspection and can promote corrosion); however, if you do tape them to prevent snagging, remove the tape regularly for maintenance checks.
Check the mast for loose or missing hardware (screws, rivets) and corrosion, particularly at the gooseneck, spreader tips, welds, or any place stainless steel contacts aluminum. A white powdery residue or blister indicates aluminum corrosion, meaning the area must be cleaned and further inspected immediately.
Finally, take a good look at the mast step. For keel-stepped masts, check that the bottom of the mast and the step itself are free from damage and corrosion (a common problem for anything located in the bilge) while looking for signs of cracked or crushed floor frames, grids, or other support structures.
For deck-stepped masts, look for deck issues around the step, such as fiberglass crazing, stress cracks, and deck failure or compression. This is typically the result of delamination and loss of structural integrity due to moisture entering the coring (often through the mast step mounting hardware). Belowdecks, check the mast compression post or support bulkheads that transmit the load of the mast to the hull.
Shrouds & Stays
Start your inspection with an overall view of all wire rigging for general issues, such as kinks or sharp bends, which indicate the wire’s structural integrity has been compromised. Pitting or a dull, rusted appearance also warrants a closer look and possible replacement. Thoroughly inspect the entire length of each wire, with special emphasis on the terminals or end fittings, the most common points of failure (more on this in a moment).
Broken wire strands (aka fishhooks) along the wire is another thing to watch for. Check for broken strands by encircling the wire with a handful of tissue paper, then lightly drag it the entire length in both directions (a nylon stocking works great for this as well). Fishhooks will be indicated as they snag the paper – just be sure not to hold the paper too tightly, or any hooks may get a little flesh as well.
Take a close look at head and backstay fittings (top and bottom) as well as any roller furling systems. Furlers should be inspected and serviced per the manufacturer’s recommendations. At a minimum, they should be completely disassembled for inspection every 10 years. Replacement of the headstay at that time (if greater than 10 years old) is also recommended.
The deck below a deck-stepped mast is vulnerable to water intrusion, cracking, and crazing, which can all lead to a loss of structural integrity. Photo, Frank Lanier
Photo, Frank Lanier