The UK MAIB has reported a case in which a tanker’s bow collided with the fishing vessel’s port side, causing extensive damage below the waterline in way of a wing fuel tank between the fish hold and the engine room vessel’s port side.
The incident
The early morning watch for a tanker’s OOW and OS lookout was uneventful. The vessel traffic was light despite navigating through an area in which several traffic lanes converged.
The only radar target of interest was a fishing vessel several miles ahead that the tanker was slowly overtaking. Both the tanker and the fishing vessel were on south-westerly headings and the OOW estimated that the tanker would not overtake the fishing vessel for over 1 hour. The OOW decided that it was a good opportunity to repair a defective dimmer switch on the chart table light. However, the repair required spare parts, so the OOW left the bridge to find them.
At about the same time, the fishing vessel, which was towing its nets, altered course towards the north-west. The distance between the tanker and the fishing vessel now started to decrease much more quickly. This did not alarm the OS who, although alone on the bridge, was able touse the radar to determine that there was no immediate risk of collision. The CPA of the fishing vessel was 9 cables.
Everything appeared to be under control until, several minutes later, the fishing vessel altered course to the north and its CPA reduced to 5 cables. This caused the ARPA collision alarm to sound. The fishing vessel was only 2.5nm ahead so the OS adjusted the autopilot 5° to port in order to increase the passing distance between the two vessels. However, when the distance between the vessels was about 1nm, the fishing vessel continued to turn to starboard, across the tanker’s bow. The fishing vessel’s wheelhouse watchkeeper had not seen the tanker and was turning to join a route pre-set on a track plotter. The tanker’s OS immediately recognised the danger and attempted to contact the OOW, who by that time had been away from the bridge for over 20 minutes. He was unsuccessful.
The tanker’s bow collided with the fishing vessel’s port side, causing extensive damage below the waterline in way of a wing fuel tank between the fish hold and the engine room. There were no injuries, but the crew of the fishing vessel were very fortunate. Had the damage been either side of the fuel tank, the resulting flooding of either the fish room or the engine room would probably have caused the fishing vessel to quickly founder.
Lessons Learned
1. An OOW is required to keep his/her watch on the bridge for good reasons. Navigation and collision avoidance aside, the OOW also needs to be available to respond to emergencies such as fire, machinery breakdown and man overboard. Delegation and keeping lookouts involved during a watch are signs of good management, but there is a limit. If there is an urgent need to leave the bridge when on watch, play safe and call another qualified OOW for assistance, no matter how quiet a watch might seem. Failing that, get someone else to sort the problem or leave it until the watch is over.
2. Assumptions are great contributors to accidents. To assume that another vessel will maintain its heading or will keep clear or take a certain course of action (even if it is obliged to do so) is asking for trouble. Keeping a good lookout, closely monitoring the movements of nearby vessels and checking that an intended heading is clear before altering are the only ways to help to prevent nasty surprises.
Source : UK MAIB Safety Digest 2/2016
