Independent guide: Masts are primary structure. Repairs and modifications should be designed and carried out by an experienced mast builder or rigger.
Quick answer
A yacht mast is a column held in place by the standing rigging. It carries compression from rig tension and sail loads, and bending from sails and spreaders. Most production masts are aluminium extrusions; performance and large yachts often have carbon, and classic yachts timber. Masts fail most often at fittings — tangs, spreader roots, the masthead and the heel — through corrosion, fatigue or overload, which is why mast-out inspections focus there.
Mast materials
| Material | Typical boats | Strengths | Watch for |
|---|---|---|---|
| Aluminium | Most cruisers, catamarans, trailer sailers | Economical, repairable, widely available | Galvanic corrosion at fittings, fatigue cracks — see aluminium masts |
| Carbon fibre | Racing boats, performance cruisers, superyachts | Light, stiff | Impact damage, delamination, hardware bond failure — see carbon masts |
| Timber | Classic yachts | Traditional, repairable | Rot, glue-line failure, fastening corrosion — see classic rigging |
How the mast is supported
- Keel-stepped masts pass through the deck to a step on the keel, supported at the deck partners.
- Deck-stepped masts sit on a shoe on deck over a compression post or bulkhead.
Each has its own inspection points. See keel-stepped vs deck-stepped masts and mast step and compression structure.
Mast fittings that matter most
| Fitting | Job | Common issue |
|---|---|---|
| Masthead | Carries forestay, backstay, cap shrouds, halyard sheaves | Cracked welds, worn sheaves |
| Tangs | Attach shrouds and stays | Cracks, elongated holes, corrosion |
| Spreaders and roots | Widen shroud angle | Root cracks, loose bases, tip wear — see spreaders |
| Sheaves and exits | Guide halyards | Wear, seized axles, chafe |
| Gooseneck | Connects boom | Pin and bush wear |
| Heel and step | Carries compression | Corrosion, crushing |
| Wiring and conduit | Lights, instruments, antenna | Chafe, corroded connectors — see mast wiring |
Inspecting a mast
From deck, look up the track for straightness and check the base, gooseneck and exits. Aloft, inspect the masthead, tangs and spreaders — see how to inspect a mast aloft. The most complete inspection is a mast-out service, with the mast on trestles and fittings removed.
Mast services
Masts by boat type
- Catamaran masts are tall and deck-stepped over a compression post.
- Trailer sailer masts pivot in a tabernacle and are raised often.
- Racing yacht masts are often fractional, with runners and higher tensions.
- Classic yacht masts are frequently timber.
Related guides
- Standing rigging
- Rig tuning
- Booms and bowsprits
Frequently asked questions
How long does an aluminium yacht mast last?
A well-maintained aluminium mast can last for decades. Its life is usually ended by corrosion around fittings, fatigue cracking at highly loaded points, damage in an incident, or the extrusion becoming obsolete so fittings cannot be sourced, rather than by age alone.
What is the most common problem with aluminium masts?
Galvanic corrosion where stainless fittings and fasteners meet the aluminium, shown by bubbling paint and white powder. Left alone it loosens fittings and can undercut them. Treatment involves removing the fitting, cleaning out corrosion and refitting with an isolating compound.
Common questions
- How do I inspect a mast aloft safely?
Going aloft safely requires two independent attachment points, a halyard whose full length and terminal have been inspected first, a competent person tending the winch, and a plan that never relies on a rope clutch alone. Many owners are better served paying a rigger who goes aloft daily and carries the right equipment.
- How do I prepare my yacht for a re-rig?
Prepare for a re-rig by photographing and measuring the existing rig before anything is removed, recording current tuning settings, labelling every wire and halyard, clearing access to chainplates and the mast step, and agreeing in writing what happens if extra work is found once the mast is down.
- How is a yacht mast unstepped?
A mast is unstepped by disconnecting deck-level wiring and plumbing, slackening and releasing the standing rigging in a controlled order while a crane takes the weight, lifting the spar clear, and laying it on padded trestles. It is crane work with people beneath a suspended load, and is not an owner task on a keel-stepped rig.
- How do I check my mast is straight?
Check mast straightness by sighting up the mast track from directly beneath it at the gooseneck: the track should run straight with no sideways bend. Athwartships centring is confirmed by running a halyard to the same point on each toerail. Check both at the dock and again under sail on each tack.