202551 Fatigue claims another victory

As edited from USCG Safety Alert Safety Alert 02-25

A towing vessel in a river waterway was pushing a barge loaded with aggregate when the lone operator in the wheelhouse fell asleep at the helm. The barge struck a bulk liquid transfer terminal, resulting in more than $1.5 million in property damage to the barge, handling equipment, and the facility.

The investigation identified the failure of the Wheelhouse Alerter System (equivalent to a BNWAS) to detect the lack of motion from the operator as a key contributing factor. The system relied on passive infrared (PIR) detectors to monitor motion in the wheelhouse, and was set to sound an alert if no motion had been detected for ten minutes. However, the PIR sensors were tripped by non-human movements such as swinging cables and oscillating fans, causing the system to continually reset the timer – and thus failing to detect the operator’s inactivity. Additionally, the system used was not designed by a marine equipment manufacturer, which raises concerns about its reliability in marine environments.

Lessons learned

• Although the Wheelhouse Alerter System did not function as required, neither did the operator. He fell asleep. Why? Crew work schedules, minimum safe manning numbers, company policies, crew practices…just a few of the possible upstream underlying factors.
• A single operator in the wheelhouse is a classic example of potential ‘single point failure’.