The rig is the most heavily loaded and least inspected system on a sailing yacht. That is why underwriters start asking questions once standing rigging passes ten years: a rig failure is rarely limited to losing the mast, deck, chainplates and often crew safety are involved.
Scope: mast and boom · standing rigging (wire, terminals, tangs) · running rigging · chainplates and deck fittings · furling systems · winches and clutches · tension measurement with a Loos & Co. gauge · observation of the keel-hull area.
1. Why Tension Cannot Be Judged by Hand
Correct tension is a defined percentage of the wire's breaking load (typically 15-20%, depending on the boat and rig type). Setting it without a gauge produces two errors:
- Slack rig: the mast moves, wire fatigues and terminals work-harden. The boat falls off upwind and performance suffers.
- Over-tensioned rig: the load goes straight into chainplates, deck and the keel area. Deck depression, leaks and cracking around chainplates start here.
- Uneven tension: a port-starboard difference leaves the mast out of column; the boat sails well on one tack and badly on the other. The most common and most easily corrected finding.
With a Loos & Co. gauge every wire is measured, values recorded, port and starboard compared and assessed against the builder's recommendation. The report carries numbers, not "the rig appears tight".
2. Checkpoints
Standing rigging
- Wire: broken strands (particularly at terminal exits), corrosion staining, permanent kinks.
- Terminals: crack search with a 30× loupe, a crack in a swage terminal means renewal.
- Toggles and clevis pins: wear, bending, missing split pins.
- Turnbuckle bodies and threads: corrosion, signs of strain.
Mast and boom
- Mast step: corrosion at the heel on aluminium spars, particularly deck-stepped rigs; blocked drainage.
- Sheave boxes, tracks and halyard exits: cracks usually start around openings.
- Tangs, welds and rivet lines.
- Gooseneck, kicker and vang attachment points.
Deck side
- Leak traces and salt staining around chainplates, softness in the laminate, checked with the sounding hammer.
- Staining on headlining and inside lockers; closed compartments checked with a borescope where needed.
- Mast step support structure below deck.
Running rigging and hardware
- UV fatigue in halyards and sheets, cover wear, condition of terminations.
- Furling gear: stiffness, bearing noise, even wrapping.
- Winch service: dried grease, tired pawls, torque behaviour.
3. When Should a Rig Be Replaced?
| Condition | General approach |
|---|---|
| Age | Usually 10-12 years for wire rigging; sooner with heavy use or in a hot climate |
| Cracked terminal | A single crack justifies renewal, a rig is as strong as its weakest link |
| Broken strand | That wire is replaced immediately and its neighbours inspected |
| Insurer's requirement | Many policies require a report or renewal past a certain age |
| Before an offshore passage | A rig at the age limit is renewed before a long delivery |
Planning a delivery? A long passage is the most reliable test of a rig's weakest point. A rig check and tension measurement before departure costs a fraction of losing a mast at sea.
Frequently Asked Questions
Correct tension is a defined percentage of the wire's breaking load and cannot be judged by feel. A slack rig fatigues wire and terminals; an over-tensioned rig drives load into chainplates, deck and the keel area. With a Loos & Co. gauge every wire is measured and port-starboard balance compared numerically.
Wire rigging is generally considered due at 10-12 years, sooner with heavy use or in hot climates. A single cracked terminal or broken strand justifies renewal regardless of age, a rig is as strong as its weakest link.
Wire and terminal condition, crack search with a 30× loupe, recorded tension values, chainplate and deck fitting condition, mast step and furling systems. Numerical values are what underwriters actually look for.
It should be taken seriously. Salt traces and corrosion indicate water entering the laminate; staining on the headlining means the area should be opened and inspected. The surrounding laminate is checked by sounding and, where necessary, with a borescope.
Not always. A routine assessment can be made with the mast standing. Where there is doubt about terminals, on an older rig, or when a renewal decision is being made, unstepping for full inspection is recommended. Areas that could not be inspected for this reason are stated clearly in the report.
4. Book a rig check and tension measurement
Every wire measured, values recorded, port and starboard balance compared.
Related Pages
Our StandardsMethod, equipment, ethics, liabilitySurvey TypesWhich survey do you need?Survey Report ContentsWhat the report containsCommon Boat DefectsThe 20 findings we record most
Prepared by SurveyYat, ABYC Professional Member, 149 GT Yacht Captain. Last updated: September 2026.
Scope: The survey is non-destructive and nothing is dismantled; details on the survey types page.
Findings we often see on site
- Hairline crack in a rigging terminal: A lengthwise hairline crack at the neck of a lower shroud terminal, seen under the loupe.
Continue with this topic
- Rudder and bearing renewal: From measuring play to acceptance.
- Rig and mast renewal: The decision and the sequence.