How does a yacht's standing rigging actually work?
I'm looking to buy my first cruising yacht, probably a 1990s Moody or Westerly. Surveyors keep mentioning the age of the standing rigging. I know it holds the mast up, but how does the system actually work and why is it under so much tension?
Answer
Standing rigging is the network of fixed wires or rods that keeps a yacht's mast upright and transfers the driving force of the sails directly into the hull. It works purely in tension, balancing opposing pulls from the bow, stern and sides to keep the aluminium or carbon spar perfectly in column.
Primary wires and roles
A mast is a compressive strut pushing down onto the keel. A web of tensioned wires holds it in place.
- Forestay: Runs from the masthead to the bow. It stops the mast falling backwards and provides a taut leading edge for the jib or genoa.
- Backstay: Runs from the masthead to the stern. It stops the mast falling forwards and is often adjustable to bend the spar. This flattens the mainsail in strong winds.
- Cap shrouds: Run from the upper mast down over the tips of the spreaders to the deck. These take the massive lateral loads when the boat heels.
- Lower and intermediate shrouds: Secure the middle sections of the mast to the deck. They stop the mast from bowing out of column or pumping in a seaway.
Never work directly beneath a mast being stepped or unstepped. A single dropped clevis pin can bring the entire rig down instantly.
Materials and deck hardware
On most cruising yachts, such as a Moody or Westerly, the standing rigging is made from 1x19 stainless steel wire (grade 316). The 1x19 designation means it is a single bundle of 19 individual strands. This makes it incredibly strong and resistant to stretch, though highly inflexible. Wire diameters typically range from 6mm on a 28-footer to 12mm on a 45-foot cruiser.
Modern performance yachts often use solid Nitronic 50 rod rigging for less stretch, or synthetic cables like Dyneema SK99 to save weight aloft. The wire ends are terminated with machine-pressed swages or mechanical fittings like Sta-Lok or Norseman terminals. At deck level, the wires attach to chainplates via rigging screws, also known as turnbuckles. High-quality rigging screws from brands like Seldén or Hasselfors pair a stainless steel screw with a bronze body. This prevents the threads from galling and seizing under extreme loads.
Mechanics of rig tension
Standing rigging does not hang loosely. It is heavily pre-tensioned. The spreaders act as compression struts, pushing the cap shrouds outwards to widen the angle between the wire and the mast. This increases the mechanical advantage and reduces the overall load on the wire.