“Heavy weather” for ship navigation explained

The term “heavy weather” is defined as combination of strong winds of Beaufort scale 7 or more and waves with height of 4 meters or more. A tropical storm is developed over tropical oceans and is a very intense low-pressure wind system with winds of hurricane force. Tropical storms consist of rotating masses of warm and humid air and create thunderstorms with high waves, flooding rain and strong winds.

Lessons Learned: The importance of “heavy weather” checks

In 2008, a container vessel departed from Le Havre to Algeciras, Spain in force 4 to 5 winds. Overnight the weather deteriorated and the vessel’s speed was reduced. By 1200 the wind had further increased to force 8 to 9 with rough seas. At 1250 the bow thruster room bilge alarm sounded and a number of holes were found in the port side of the bow thruster room shell plating through which water was pouring. The port anchor chain lashing was found to have released and the anchor had fallen, against the windlass brake tension, into the water. As the vessel continued to pitch in the heavy seas, the anchor impacted against the hull, causing the damage. It was later found that five adjacent compartments had also flooded. Despite the forecasted poor weather conditions, no specific heavy weather checks had been carried out. The incident reveals how important preparation is, since a prewarning on weather conditions is available.

Actions to be taken under heavy weather conditions or tropical storms

  • Master and Engine Room should be informed of the weather conditions
  • Crew should be advised to avoid upper deck areas
  • Safety lines and hand ropes should be rigged where necessary
  • Vessel’s course and speed should be adjusted
  • Necessary maneuvers should be made in order to minimize the risk of damages
  • Weather reports should be monitored and reported to the appropriate authorities. In the case of tropical storms, danger messages should be done in accordance with SOLAS requirements
  • Vessel’s accommodation should be secured
  • Vessel’s machinery and movable objects on deck, engine room, galley and storerooms should secured
  • Weather deck openings, ports and deadlights should be closed
  • Cargo should be secured as appropriate

SQE Marine has prepared a checklist aiming to provide the necessary steps required, to achieve vessel’s preparation and response during heavy weather or tropical storms.