A typical example of heavy weather damage is damage to the vessel’s hull, such as indentations in the vessel’s bottom, particular in the forepart. Damage from pounding can be extensive, and occurs relatively frequently. The risk of such damage is greatest when the vessel is in ballast, and could in many cases have been avoided by adjusting speed or by altering course. Damage to the deck is also characteristic of weather damage, where bulwark, stanchions and breakwaters, as well as equipment on the vessel’s forecastle, are particularly vulnerable.
Always record damages caused by heavy weather in the logbook, and keep records of the vessel’s behaviour in heavy weather under different loading conditions. This is a vital resource for averting heavy weather damage. Maintain awareness of the crew’s physical and emotional states during heavy weather. Counter any parametric rolling.
The vessel should always be fully prepared for sea before leaving port. Previous experience shows that the following are the most frequent causes of heavy weather damage on the trade route:
Heavy weather damage to the vessel’s hull, superstructure, and/or cargo is most frequently caused by running at a speed that is incompatible with the force and/or direction of the sea and swell. The vessel’s speed is the most crucial factor in heavy weather damage.
Incorrect distribution of weight
Factors contributing to heavy weather damage include the metacentric height, shifting cargo, or wrong ballasting during ballast voyage. Avoid slack in tanks, and water in bilges and suction wells. Always keep in mind the free surface effects, and prepare plans and steps to change stability/trim before the weather deteriorates. Anti-rolling/anti-heeling tanks shall be prepared for immediate use if possible.
Loss of stability
Loss of stability and increased stress/bending occurs when riding on waves. When sailing with the wind and waves, the most important factor to avoid is high speed, which can cause surfing and broaching. A vessel seldom suffers damages to the hull through rolling, but the risk for damage to its cargo and equipment/gear naturally increases with violent rolling.