Chartwork is a crucial skill for any sailor or mariner. It involves the use of nautical charts to navigate a ship safely and efficiently. One aspect of chartwork is allowing for the leeway caused by wind and the set of current on a ship's course and speed.
When a ship is underway, it is subject to the forces of wind and currents. These external factors can affect the ship's actual track over the ground, deviating it from the intended course. To compensate for this, chartwork involves making adjustments to the planned course and speed.
To calculate the leeway caused by wind, sailors consider the ship's characteristics, wind direction, and strength. By estimating the leeway angle, they can determine the necessary correction to be applied to the intended course, ensuring the ship stays on track despite the wind's influence.
Similarly, the set of current refers to the sideways movement of water that can affect a ship's course. By analyzing information from tidal charts, current atlases, or hydrographic publications, sailors can determine the direction and strength of the current at a specific location and time. This knowledge allows them to adjust their navigation plan accordingly, compensating for the potential drift caused by the current.
By accounting for both leeway and set of current, mariners can accurately plot their ship's expected course and speed on the chart. This ensures the vessel stays on the desired track and reaches its destination safely.
Remember, chartwork requires careful observation, accurate measurements, and constant adjustment. It is an essential skill for sailors to master, enabling them to navigate effectively and avoid potential hazards while at sea.
