The boat is empty for ten days between charters and the engineer suggests dropping the AC to save fuel. The saloon will sit at 34 C and whatever humidity the Med feels like. There is a nineteenth-century marquetry commode against the aft bulkhead and two canvases on the wall behind the sofa. This is the moment the collection is quietly damaged, and nobody will notice for a year.
Stability Beats Perfection
Works of art adjust to their conditions. What harms them is change: fast, repeated swings in temperature and relative humidity that make hygroscopic materials expand and contract until something cracks, lifts or splits. A steady, slightly imperfect environment is far kinder than a perfect one that cycles.
- Aim for a stable temperature and a stable RH, broadly in the region of 45-55% RH, and hold it.
- Keep the AC running when guests are away. The cost of running it is trivial next to a claim.
- Keep doors, hatches and portholes shut in port and at sea. Salt air is the enemy.
- Report humidity spikes, condensation and any smell of damp to the chief stew and the engineer.
The AC Is Both Saviour and Enemy
Air conditioning holds the environment - and then it blows a cold, dry, fast-moving jet straight at whatever is in front of it.
| Hazard | Effect on the work | Control |
|---|---|---|
| Direct AC vent | Local drying, chilling, dust deposition | Never hang or place art in the airflow |
| Porthole or open door | Salt aerosol, humidity swing, UV | Keep art off those bulkheads entirely |
| AC switched off in port | Heat and RH spike, mould | Keep the system running; agree it in writing |
| Condensation on a cold bulkhead | Water at the back of a canvas or frame | Report; do not hang on cold outer bulkheads |
Light: The Damage That Cannot Be Undone
- No direct sunlight, ever. Not for an hour, not on a cloudy day.
- Use UV-filtering glazing on works on paper and photographs, and UV film on windows where art is in the room.
- Close blinds and shades in unoccupied spaces. This is a daily interior job, not an occasional one.
- Aim spotlights so the beam misses the work. A tight halogen spot on a canvas is a heat gun as well as a light.
- Keep light levels low for paper, textiles and photographs, and support rotating them off display.
Position Is Prevention
Most of preventive conservation onboard is simply where a thing is. Away from vents, portholes, doors, heat sources, galley and laundry bulkheads, walkways, swinging doors, bar tops and drinks tables. If you think a piece is badly positioned, say so - and let the art adviser move it, not you.
Onboard Notes
- Record temperature and RH where the collection lives if the boat has the means. Trends matter.
- Blinds closed, doors shut, AC steady. That is most of the job, done every single day.
- Never reposition art yourself to solve an environmental problem. Report it and escalate.
- Nothing in this lesson authorises anyone to clean or treat a work of art.