Unmanned Machinery Space
Abbreviation: UMS
Engine room operated without engineer watch present, relying on automation, alarms, and a duty engineer on call.
In practice
Class notation E0 / UMS / AUT requires alarm transfer to bridge and accommodation, dead-man alarm in the engine control room, and class-tested safety arrangements. The duty engineer carries the dead-man pager during night hours.
Regulatory detail & full definition
Required minimum class notation 'UMS' or '24-h UMS'. Must have data logger, fire/bilge/water-ingress detection, dead-man alarm tied to the duty engineer's cabin, machinery-space CCTV. Watch is suspended at sea between morning rounds; stand-by by VHF/pager. Exempt for tanker cargo operations and when operating in restricted waters.
Authoritative source: IACS Unified Requirements ↗
Related
Source: SOLAS Ch. II-1 Reg. 32; IACS UR M51 (UMS notation)
High confidence
Editorial confidence: how we grade.