On 23 February 2025, near buoy Maas 5 at the Maasmond (Rotterdam), a collision occurred between a Dutch-flagged harbor tug and a Marshall Islands-flagged tanker in dense fog. The tug was waiting to assist an incoming container ship but drifted northward, crossing the tanker’s path. At 01:49:43 UTC+1, the tanker’s bow struck the tug’s starboard side, causing a hull breach. Water flooded the accommodation, forcing the crew to ground the vessel on a shallow near Ertskade to prevent sinking. Portable pumps were used, but exhaust fumes caused respiratory issues for some crew members. The tug suffered significant damage, requiring three months of repairs; the tanker sustained minor damage.
Investigation findings (Dutch Safety Board Report, July 2026)
The incident resulted from multiple operational and procedural failures under low-visibility conditions:
- Loss of positional awareness: The tug’s crew, accustomed to visual navigation, failed to detect their gradual drift into the shipping lane due to fog. Radar, ECDIS, and gyrocompass, which are critical in such conditions, were underutilized. The crew lacked training in instrument-based navigation and bridge team coordination for restricted visibility.
- High speed & insufficient stopping distance: The tanker, advised by a pilot, maintained near-full power, reducing maneuverability. No explicit agreement on a safe speed for the conditions was reached between the master and the pilot. Both assumed the tug would remain clear of the traffic lane, leading to late situation recognition.
- Poor waiting position & procedural rigidity: The tug anchored near the fairway’s edge, where strong currents increased drift risk. No predefined safe waiting positions for tugs existed in low visibility, and the Port of Rotterdam set no requirements for such scenarios. The tug assistance request procedure demanded early commitment without reassessment options as conditions deteriorated.
- Communication gaps: The pilot-master exchange (briefing) did not explicitly address current visibility or engine settings. Mutual trust replaced active coordination: the pilot assumed the tug would stay clear, the captain relied on the pilot, and traffic control lacked real-time tug positioning data.
- Late detection: The tug’s crew believed they were safely off the fairway, as a buoy remained visually ahead. The tanker’s crew only recognized the tug’s hazardous position too late, leaving insufficient time to avoid collision.
The investigation concluded that activating the fog protocol would not have prevented the accident, as it focuses on pre-planning rather than real-time operational decisions.
Key recommendations
- Enhanced training for tug crews:
- Regular drills on navigation in limited visibility, including radar/ECDIS use and bridge team role clarity (e.g., designated navigation/communication tasks).
- Port of Rotterdam’s role:
- Establish safe waiting positions for tugs in fog.
- Revise assistance request procedures to allow reassessment when visibility worsens.
- Facilitate ongoing dialogue between pilots, tug companies, and port authorities.
- Pilotage adjustments:
- Expand the pilot-master exchange to explicitly discuss engine settings suitable for low visibility, ensuring a shared understanding of safe speed.
The incident underscores the need for proactive risk management in dynamic conditions, with clearer protocols, training, and communication to prevent similar accidents.