Unattended Machinery Space and the Silenced Engineer Alarm
A 9,500 GT chemical tanker has a periodically unattended machinery space notation. At sea at night, the engine room control room is unmanned and the bridge watchkeeper monitors the alarm panel. The duty engineer is asleep in a cabin one deck below. During an inspection, it is found that the engineer's alarm in the duty engineer's cabin has been disconnected because it disturbed the off-duty engineer in the adjacent cabin. The bridge alarm panel is working, but the 'alarm acknowledged' button has been taped down so that alarms are silenced automatically. The high-level bilge alarm for the engine room was isolated two weeks ago after a false alarm caused by a leaking ballast valve; the leak has not been repaired. The duty engineer has been on call for 14 hours and had 4 hours of sleep. The master says the arrangement is normal for a UMS ship and that the bridge watchkeeper checks the panel every 30 minutes. The vessel is on a 10-day voyage.
1. Identify the UMS alarm and safety deficiencies under SOLAS II-1 Part E and explain the risk.
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A periodically unattended machinery space depends on alarms being transmitted reliably to the bridge and to the engineer who is on call. The engineer's cabin alarm is part of that chain. Disconnecting it because it disturbed another officer removes the means of summoning the duty engineer when the bridge needs assistance. The taped acknowledge button defeats the escalation logic: alarms are silenced automatically instead of requiring acknowledgement and, where necessary, transfer to the engineer's cabin. The isolated high-level bilge alarm removes warning of flooding in a machinery space, and the underlying ballast leak has not been repaired.
The risk is cumulative. A single alarm failure might be tolerable only with compensating arrangements; here the bridge alarm, the engineer call and the bilge alarm are all degraded at the same time. The 30-minute panel check does not replace an audible alarm and escalation system, because a watchkeeper occupied with navigation may not look at the panel in time. These are deficiencies against the UMS alarm and safety requirements and against the safety management system.
2. Can the ship continue in UMS mode? What immediate measures and operating restrictions should apply?
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The ship should not continue in UMS mode until the alarm chain is restored. The immediate measures are to reconnect the engineer's cabin alarm, remove the tape from the acknowledge button, repair the ballast leak, restore the high-level bilge alarm, and test each alarm from the sensor through to the bridge and the engineer's cabin. The tests should include an unacknowledged alarm to prove that escalation works.
If the repairs cannot be completed at once, the machinery space should be manned or a continuous watch should be posted in the control room, and the bridge should be informed of the degraded alarms. The master should also address the fatigue issue: a duty engineer who has had four hours of sleep after 14 hours on call is not a reliable part of an alarm-response system. A relief engineer or an adjusted watch schedule should be arranged. Flag State and class should be notified of the UMS deficiency.
3. How should alarm management and human factors be addressed so that the fix is not only technical?
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The technical repair should be accompanied by an alarm-management review. The engineer's alarm should be audible in the cabin but not in adjacent cabins unnecessarily, and its priority should be clear. The acknowledge button should require a deliberate action and should not be capable of being taped down without being noticed. Nuisance alarms, such as the false bilge alarm caused by the leaking ballast valve, should be treated as maintenance defects rather than silenced permanently.
The review should also cover fatigue and response expectations. The bridge watchkeeper needs a clear procedure for when to call the engineer, and the engineer needs a realistic rest period. Drills should include an unacknowledged machinery alarm at night, with observation of how long it takes to reach the engineer. The master should record the review and the changes, because the underlying problem is a culture of silencing alarms rather than a single broken wire.