Visual Navigation Implicated in Container Ship Grounding

Leda Maersk
Leda Maersk

Published Oct 24, 2019 6:47 PM by The Maritime Executive

The New Zealand Transport Accident Investigation Commission has released its report into the grounding of the Leda Maersk citing reliance on visual navigation as a factor in the incident.

On June 10, 2018, the Danish-registered container ship arrived off the Port of Otago, embarked a harbor pilot and proceeded up the Lower Harbour channel at about 1800, during the hours of darkness. The master, officer of the watch and helmsman were on the bridge, with the harbor pilot directing the course and speed of the ship.

The ship was rounding the final bend in the channel before reaching its berth, when a combination of factors caused her to deviate from the planned track in the center of the channel and ground on the left channel bank. Nobody was injured, and damage to the ship was confined to scraping of the paintwork on the hull.

The Transport Accident Investigation Commission found that neither the harbor pilot nor the ship’s bridge team recognized that the Leda Maersk was deviating from the planned track because they were all primarily navigating using visual cues outside the ship, rather than fully using the electronic navigation aids, all of which clearly showed the ship deviating from the center of the channel.

The pilot had discovered that his PPU indicated that the ship was slightly off track. On checking the settings, he found that there was an 18-meter offset to starboard to allow for the position of the PPU aerial in relation to the ship’s centreline. The offset was causing the PPU to indicate that the ship’s position was 18 meters, approximately half the ship’s breadth, further to port than it really was. He was unable to remove the offset so decided to discontinue using the PPU for monitoring the ship’s progress. Instead the pilot conned the ship visually and used the ship’s radar as an aid. The pilot did not tell the rest of the bridge team that he had stopped using the PPU.

Subsequently, the pilot gave a succession of large helm orders to port. As the Leda Maersk responded to the port rudder, the deviation left of the planned track increased, causing the off-track alert on the ECDIS to activate. The ECDIS log recorded that the off-track alert had activated and that a member of the bridge team had acknowledged it. However, the information was not passed on to the other members of the bridge team.

The Commission found that the standard of bridge resource management on the bridge of the Leda Maersk fell short of industry good practice and that the Leda Maersk bridge team were not fully following the company policies and procedures for navigating in pilotage waters.

The Commission also found that, at the time of the grounding, Port Otago’s policies, procedures and compliance monitoring of pilotage operations fell short of meeting good industry standards outlined in maritime rules and the New Zealand Port and Harbour Marine Safety Code.

The Commission recommended that the Chief Executive of Maersk Line A/S review the implementation of the company’s safety management system across its fleet with respect to navigation and pilotage and take the necessary steps to ensure a high standard is achieved by all crews on all its ships.

The Commission also recommended that the Chief Executive of Port Otago continue to take the necessary action to ensure its pilotage operations meet good industry practice and the guidance provided in the New Zealand Port and Harbour Marine Safety Code.

The Commission highlights some key lessons:

- there must be an absolute agreement and shared understanding between the vessel’s bridge team and the pilot as to the passage plan and monitoring against that plan

- vessels’ bridge teams must actively promote and use the concept of bridge resource management, including the incorporation of pilots into the bridge teams, to manage voyages properly

- a vessel’s electronic chart display and information system is an important system for monitoring the progress of the vessel and warning the bridge team when things could go wrong. It is essential that it be configured correctly for the phase of navigation and the proximity to navigation hazards.

- portable pilot units can be useful aids to navigation and their accuracy is well suited to allowing pilots an independent means of monitoring the progress of large ships in narrow channels. However, if pilots are to use them, they should be fully trained and proficient in their use, and there should be a robust system for ensuring the accuracy of the equipment.

The report is available here.