An articulated tug and barge (ATB) grounded after the officer of the watch (OOW) fell asleep while navigating in confined coastal waters. The tug was pushing an oil barge in ballast when the OOW, who was alone on the bridge acting as both navigator and lookout, took over the watch at 23:00. After successfully completing a planned course alteration at 00:20, the OOW missed a subsequent alteration about 30 minutes later after falling asleep in the bridge chair.

Shortly after 01:00, the ATB struck a charted reef. The impact awakened the OOW, who attempted emergency maneuvers. The Master, alerted by the grounding, assumed command but was unable to free the vessel. Worsening sea conditions led to a fuel leak from the tug, and the crew was evacuated approximately eight hours later. Salvage and environmental response operations lasted 40 days. The tug was declared a constructive total loss, while the barge was salvaged and repaired.

Investigators determined that fatigue was a primary causal factor. The OOW was experiencing both acute and chronic sleep disruption, circadian rhythm disturbances and individual fatigue-related vulnerabilities. The case underscores the importance of sleep hygiene, bridge resource management and physical alertness while on watch, particularly in confined waters.