Independent guide: Structural mast repairs should be designed and carried out by an experienced mast builder or rigger.
Quick answer
Most mast repairs on Australian yachts deal with corrosion where stainless fittings meet aluminium, wear at sheaves and halyard exits, and damage at spreader roots, tangs and the mast base. Local damage is usually repairable; a crack or kink in the main section, or widespread corrosion, may mean a new mast. Repairs are best done with the mast out — see mast-out rig service.
Common repairs
| Problem | Typical repair |
|---|---|
| Corrosion under fittings | Remove, clean, treat, refit with isolating compound and new fasteners |
| Loose or corroded rivets | Drill out and replace with suitable rivets or machine screws |
| Worn sheaves and axles | Replace sheaves, bushes and axle pins |
| Chafed halyard exits | Replace exit plates, fair sharp edges |
| Spreader root damage | Replace spreader bases or brackets; check the section around them |
| Cracked welds at masthead | Re-weld where appropriate, or replace the masthead casting |
| Dented section | Assess depth and location; sleeve or replace the section |
| Mast base compression damage | Replace heel casting; check step and support |
Aluminium, stainless and salt
Most production masts are anodised or painted aluminium with stainless fittings and fasteners. In salt water, aluminium in contact with stainless corrodes. It shows as bubbling paint, white powder and loose fasteners. Left untreated, corrosion can undercut a fitting until it pulls out under load. See aluminium masts.
Carbon and timber masts
- Carbon masts need specialist inspection for impact damage, delamination and hardware bond failure. See carbon masts.
- Timber masts need moisture checks, glue-line inspection and attention to fastenings — see classic yacht rigging.
Repair or replace?
Replacement becomes more likely when:
- the extrusion is discontinued and fittings are no longer made
- corrosion is widespread rather than local
- the section is cracked or kinked
- the boat's programme needs a stiffer or lighter mast
By boat type
- Catamarans: tall masts, often rotating on some performance designs; mast base and ball fittings need inspection.
- Trailer sailers: tabernacle and mast-foot damage from repeated raising.
- Racing yachts: high loads on runners and checkstay tangs.
- Charter yachts: in-mast furling mechanisms and heavy usage.
Frequently asked questions
Can a cracked aluminium mast be repaired?
Sometimes. Small cracks at fittings can often be repaired with a doubler or sleeve designed by an experienced mast maker, but cracks in the main section, particularly near the spreaders or partners, may mean a new section. The repair must restore stiffness as well as strength, so it is a specialist job.
What causes white powder around mast fittings?
White powder or bubbling paint around stainless fittings and fasteners on an aluminium mast is usually galvanic corrosion: the aluminium corrodes where it contacts stainless in the presence of salt water. The fitting should be removed, the corrosion cleaned out and the fitting refitted with an isolating compound and new fasteners.
Should I repair or replace an old mast?
Repair when the damage is local, the section is otherwise sound and parts are available. Replace when there is widespread corrosion, a kink or crack in the section, the extrusion is discontinued and fittings cannot be sourced, or repairs would cost a large share of a new spar.