On the night of 23 February 2025, a collision occurred near Maas buoy 5 at the entrance to Rotterdam, in restricted visibility due to fog, between the harbour tug VB Seal and the tanker Gulholmen. The Dutch Safety Board (DSB) investigated the incident and concludes that ship crews need more training in navigating by instruments.
At the time of the accident, the VB Seal was waiting to assist the inbound container ship Maersk Iowa. While waiting near the buoy, the tug drifted northwards, causing it to cross the course of the inbound tanker.
At around 01:50, the tanker struck the starboard side of the tug with its bow. The collision caused a tear in the tug’s hull, allowing water to flood the accommodation. The tug was subsequently beached on a shallow area to prevent it from sinking. Material damage to the tanker was limited.
Also read: DSB investigates collision between tug and tanker
More attention needed for instrument navigation
Vessel crews need more practice in navigating by instruments, states the DSB after investigating the accident. Navigating in restricted visibility is rarely needed. When it is, there are few visible landmarks to help with orientation. This makes instruments such as radar, electronic charts and the compass the primary and most reliable means of navigation.
In order to be able to navigate safely in restricted visibility, crews need regular practice in using these instruments. This was the conclusion of the Dutch Safety Board in its investigation “Collision in restricted visibility: lessons learned from investigation into collision between tug and tanker”.
Scott Douglas, Dutch Safety Board member: ‘The occurrence also shows that in conditions of restricted visibility, close cooperation between the crew on the bridge is even more important. There needs to be a clear division of roles, with a dedicated crew member monitoring the navigation information. In the occurrence concerned, not enough attention was paid to this, meaning that it was only noticed too late that the tug was drifting towards the middle of the fairway.’
Safe waiting positions for tugs
No safe waiting position has been designated for tugs in conditions of restricted visibility. The tug involved in this occurrence took up a waiting position at the edge of the fairway. However, that position offered little room to manoeuvre, and the tug’s unintended movement took it directly into the fairway.
The lack of designated, safe waiting positions makes tugs vulnerable when visibility is restricted. Given its position and network, it would seem logical for the Rotterdam Authority to take the lead in making arrangements with tug companies regarding this matter.
Also read: DSB: Damen Shiprepair needs to improve risk management
Coordination, perception and expectations
When the captain of the tanker and the pilot were coordinating matters, they relied largely on assumptions about position and the actions to be taken. They could have contributed to a safe passage by explicitly discussing the actual weather and visibility conditions during their exchange. They could also have agreed on which engine setting was acceptable to both of them.
Also read: DSB: Stricter instructions for transfer of pilots
Recommendations
Sailing in restricted visibility requires the efforts of tugboat crews that are outside the regular working methods. Tugboat crews benefit from periodic training in sailing on instruments and the division of tasks on the bridge in limited visibility. To this end, the Dutch Safety Board makes the following recommendations.
To Boluda Towage:
Make sure tugboat crews train regularly on navigating when visibility is restricted. This training shall include at least:
- The use of navigational instruments to enable the crew to directly determine and maintain the position of the ship in the event of an unexpected transition to restricted visibility;
- An unambiguous division of tasks on the bridge for navigation, communication and position assurance.
Beyond the direct adjustments following this incident, the Safety Board sees opportunities to realise broader security gains in port practice. The Safety Board sees a connecting role for the Port of Rotterdam Authority.
To the Port of Rotterdam Authority:
Make agreements on the findings of this report with at least pilots and tugboat companies. Encourage these parties to keep talking to each other. In any case, adress:
- Determine safe waiting areas of tugboats in restricted visibility;
- The existing tugboat assistance ordering procedure. In the event of changing weather and visibility conditions, record that, in consultation with the tugboat captain, a reassessment of the assistance commitment is possible at an appropriate time.
After arrival of the pilot on the seagoing vessel, the pilot and the master gave each other the usual briefing on the ship specifications and other established information: the so-called pilot-master exchange. The master and the pilot can contribute to safe navigation if they clearly discuss the current weather and visibility conditions in this briefing and agree which engine setting is acceptable for both parties.
To the Dutch Pilotage Services:
In the pilot-master exchange, add that the pilot explicitly asks the captain which engine setting is appropriate for restricted visibility, to arrive at a shared understanding.
Picture: Collision in restricted visibility (image by the Dutch Safety Board).
