Fatigue is a causal factor in almost every modern grounding / collision investigation. STCW VIII rest hours are the legal minimum, not the safety target.
Common hazards
Single-person watches and 6-on/6-off rotations.
Port stays with limited rest opportunity.
Multiple sequential alarms during off-watch.
Self-reported rest hours that don't match reality.
Practical checklist
Record actual rest hours, not idealised hours.
Refuse non-emergency tasks during rest periods.
Take rest opportunistically in port.
Raise fatigue concerns with the Master or DPA — protected under MLC.