A collision occurs when two or more vessels make physical contact at sea, ranking among the most serious categories of marine casualty given the potential for injury, loss of life, pollution, and vessel damage.
Common Causes
- COLREGs non-compliance — failure to follow give-way/stand-on rules, improper lookout, or misjudged action
- Poor watchkeeping — inadequate lookout, distraction, or fatigue affecting the officer of the watch’s situational awareness
- Communication failures — VHF miscommunication or misunderstanding between vessels in a close-quarters situation
- Restricted visibility — fog or heavy weather compounding the difficulty of collision avoidance
Immediate Response Obligations
Following a collision, the Master has specific legal obligations under international law (SOLAS and maritime custom):
- Render assistance to the other vessel if it can be done without serious danger to your own vessel and crew
- Exchange information — vessel name, port of registry, and where bound, with the other vessel
- Report the incident to flag state and relevant authorities
- Preserve evidence — VDR (Voyage Data Recorder) data must be secured, not overwritten, following any serious incident
Investigation
Collisions typically trigger a formal marine casualty investigation, examining watchkeeping practices, COLREGs compliance, communication, and any contributing equipment or human factors.
Exam Relevance
Collision avoidance under COLREGs, and the Master’s legal obligations following a collision, are core Navigation and Ship Knowledge topics across deck officer competency exams.