Why the mast stays up

Expert yacht riggers don't make house calls at sea, so it's important offshore sailors understand their own rig and how to maintain it.

Alarge majority of cruising sailors the world over have grey hair. This means there tends to be more money to fund the cruising lifestyle but older bodies find it a little harder to dance around the foredeck changing sails.

So many crews are adapting the boat to their new limits; speed becomes less important than reliability and easier workloads. Self-reliance, always fundamental, means it is more important than ever to avoid serious mast issues because you are less able to cope with them.

KNOW YOUR RIG

Calling an expert to service the yacht’s rig in a marina is like getting a mechanic to fix the car – but riggers don’t make house

calls in the middle of the ocean, so if you’re planning to go offshore, it’s important to understand:

The mast and its associated rigging are more than just a place

The fallen spar, if still attached and lying alongside the yacht,

For all these reasons it’s worth doing everything you can to ensure the rig stays up. There are no guarantees but in almost every yacht, proper design, good quality workmanship and careful maintenance will ensure the rig remains vertical. Yacht designers strive to minimise weight aloft in the interests of boat speed but sacrificing some speed for greater reliability is a good compromise for offshore cruising.

In one day on the ocean your rig may suffer more wear and tear than over a whole year of sailing in sheltered waters.

If a yacht is built for extensive voyaging the designer will include conservative safety margins over calculated working loads but many offshore cruising boats begin life as coastal cruisers or racing yachts. The yacht designer will have specified the rig to avoid excess weight and that is probably a lower specification than for ocean sailing. A yacht raced hard in its coastal career puts further wear on the mast and rigging. If you are refitting a coastal boat for offshore, it makes sense to replace older rigging with stronger wire, especially since the yacht will be carrying a lot of heavy cruising gear.

"Don't assume that you don't need to check a rig just because it's been recently serviced."

Aluminium is the most common material used for masts and spars but over time the repetitive stress cycle weakens metal. It may also be affected by corrosion. Both reduce the safety margins allowed for when the rig was built.

The most popular material for stays and shrouds is stainless steel, which can give reliable service for many years, especially if oversized wire is used and well maintained. Stainless causes less chafe on sheets and sails than galvanised wire, which some sailors prefer. Swaged ends require the least labour to fit and are overall less expensive than other types of terminal but when water seeps into the minute spaces inside the swage, it can cause corrosion. This can lead to wire failure or a hairline crack in the swage.

Most cruising yachts will have 1 x 19 stainless rigging. This construction has an inner core of seven wires twisted in one direction and an outer layer of 11 wires twisted the opposite way. If an outer strand parts, it may serve as a warning that other strands are about to break.

A few spare parts can provide a temporary fix. Have onboard some swaged pieces of wire rigging that a rigger will happily supply at no cost from the good end of a condemned stay. Half a metre of wire is enough to attach to a damaged stay with bulldog grips. Obviously, replace the stay at the next port and check the entire rig carefully.

You can minimise water ingress by heating the swage with a hair-dryer and allowing lanolin grease

rather than water to melt into the spaces. A single strand breaking away from a swage provides a timely warning but sometimes several outer strands will part a few millimetres inside a swage. This can easily go un-noticed but can be detected by twisting the wire at the swage joint and seeing a tiny movement.

Chainplates and mast tangs are another area where failures occur. Careful inspection using high-power hobby glasses will help to find a hairline crack in stainless steel, and dye applied to fittings can show up tiny cracks. It is particularly difficult to identify corrosion of chainplates where they pass though the deck

but it helps to keep the joint well-sealed to prevent water ingress.

Chainplates often have an extra layer of metal welded on at the upper end to double the thickness. When the hole for rigging is drilled through both layers, the joint between the layers is exposed and water can seep in, causing internal corrosion which leads to unexpected failure.

Successful voyages depend on good planning and this should include planning how to address the most likely rig problems. For example, if you break a shroud: immediately use halyards to support the mast by running them to a strong point on the gunwale, stem or stern, as appropriate. Spectra and Dynema are strong and sufficiently low-stretch to make excellent stays.

While many rigs have been saved by instant action such as tacking if a shroud breaks or running flat when the forestay goes, it takes a lot of luck to have that opportunity. B