The Deep Draft

A 4,426gt cargo vessel was proceeding to her next discharge port with a draught of 5.95 metres. The master realised that he would not make the tide for berthing so he chose to embark the pilot at a point nearer his route. The revision of the passage plan was assigned to the second officer who had been aboard for a week and was making his first voyage as a watchkeeping officer. He revised the plan based on waypoints calculated and entered by another officer into the GPS navigator. He amended the passage plan by using the GPS to calculate a new course from a waypoint direct to the pilot station. He did not realise he had missed out a pre-programmed waypoint in the GPS for a position east of one of the buoys.

Having determined the new course to steer from the waypoint, he laid it off on the two smaller scale charts covering that part of the passage, but did not use the larger scale chart, which covered the area of shallow water. He did not notice that his course line intersected the five-metre depth contour to the west of the buoy.

The master did not check the amended passage plan. Nearing the pilot station, the second officer saw the first buoy and passed three cables to the east of it. Then he saw two more buoys ahead. It did not occur to him that anything might be wrong. Moments later, the ship ran aground at 14 knots.

LESSONS

-Amending a passage while at sea is not easy. In this instance the second officer used waypoints entered by someone else and failed to double-check each stage of the new plan. He did not use the largest scale chart and did not highlight potential dangers.

-Over reliance on GPS to calculate courses without checking the chart to ensure it avoids potential hazards will often have uncomfortable consequences.

-Whenever taking over a watch, a check should be made that the track drawn on the chart and entered into the GPS navigator is safe. If it passes over a shoal or sandbank and the depth of water is less than the vessel’s draught, you have a problem.

Source – UKMAIB