Glossary Term
Lockout/Tagout (LOTO)
Lockout/Tagout (LOTO) is the isolation method used to prevent machinery, circuits, valves, or other energy sources from being re-energized or reopened while people are working on them. On yachts, LOTO applies to electrical, mechanical, hydraulic, pneumatic, fuel, seawater, and stored-energy hazards. The lock secures the isolation point. The tag identifies who applied it, why the isolation is in place, and what must happen before the system can return to service.
Shipboard guidance treats LOTO as part of safe control of work rather than as a stand-alone label. IMO guidance on in-water cleaning says lock-out and tag-out procedures should follow the ship’s safety procedures and the service provider’s requirements, and that divers or dive supervisors should witness the locking and tagging of relevant equipment before entry into the water. OCIMF vessel inspection guidance sets out the wider isolation logic: agree the isolation method, discharge stored energy, use locks and tags at isolation points, test that isolation is effective, and monitor the isolation while the work remains active.
On a yacht, that can mean far more than opening a breaker. A correct LOTO sequence may include stopping rotating equipment, isolating remote starts, blanking or shutting seawater or fuel sources, depressurizing hydraulic accumulators, venting pressure, proving dead on electrical conductors, and controlling any temporary reinstatement needed for testing. Where the job crosses departments, the isolation record has to be as clear as the physical lock.
LOTO protects people first, but it also protects the yacht from preventable equipment damage and chaotic restart conditions. It works best when linked tightly to the permit system and to the relevant electrical and electronic or mechanical work package so that isolation, testing, and handback follow the same control chain.