Wind forces, mooring strategies, and common high-wind challenges.

As the American Club warns, the unpredictable force of the wind, often underestimated, significantly impacts large sail area (profile) vessels, especially when moored. 

Their large sail areas expose them to potential beam wind hazards, leading to risks like a vessel breakaway that can result in a grounding, allision, collision, or damage to third party property.

Factors affecting mooring 

If the vessel captain decides to stay moored after considering the expected wind speed, estimated wind load, and other general considerations, the vessel should deploy extra mooring lines taking into account the following factors:

§  Conditions and age of the mooring ropes;

§  Brake render settings of the mooring winches;

§  Availability and safe working load of shore/terminal mooring points;

§  Conditions of shore/terminal mooring points;

§  Maximum number of moorings allowed to each mooring point;

§  Mooring pattern/arrangement and lead of the mooring lines;

§  Terminal recommendations for mooring arrangements;

§  Availability of tug assistance and linesmen that may be required to assist on short notice;

§  Potential wake effects of passing vessels on moored vessels;

§  Any forthcoming high tides or currents at the location that can put additional strain on the mooring lines;

§  Availability of clear and constant communication between the ship’s crew, the terminal staff, and tug operators; and

§  Familiarity with port and terminal procedures, rules and guidelines that are relevant to mooring in high wind conditions, as may be applicable.

Complications

There are several mooring operations related complications that may arise during periods of high winds that should be considered:

§  overloading bollards due to the load from one or multiple mooring lines

§  using older and weaker mooring lines

§  incorrect settings on constant tension winches or winch render settings

§  lack of situational awareness and monitoring of weather conditions

§  inability to deploy additional mooring lines due to unavailability of line handlers

Lessons learned

§  Plan for the expected weather, especially if wind gust velocities are anticipated to be high.

§  Plan the mooring arrangement in advance of arrival as ashore mooring points can vary

§  Know the capacities of the available mooring points ashore.

§  Increasing the number of mooring lines before the weather deteriorates is much easier.

§  Anticipate that thunderstorms can often include high winds.

§  Training and drilling for high wind events can include line handling drills, emergency departure and engine start drills, and ensuring crew readiness in an actual situation.

§  Establish and prepare an emergency action plan to mitigate the consequences of a mooring failure or vessel breakaway. For large sail (profile) vessels, such considerations should be part of the safety management system’s emergency preparedness procedures.

§  Perform a risk assessment before the vessel is berthed to help identify any possible issues and to enable planning for mitigation actions.

§  Identify and liaise with local port authorities and meteorological departments.

§  Cooperation with these authorities can be beneficial for gaining an understanding of local weather patterns and berth characteristics.

See full alert here

https://safety4sea.com/wp-content/uploads/2023/07/AmericanClub-Mooring-Precautions-for-Vessels-with-Large-Sail-Areas-When-Expecting-High-Winds-2023_05.pdf