USING WIND AND CURRENT TO ADVANTAGE
Too often the seaman brings a shoreside mentality aboard ship and looks upon wind and current as a problem to be overcome, rather than as aids to be used with the rudder, engine, tugs, and anchor to put the ship alongside a berth in a safe and seaman like manner. A powerful tug can combat a moderate wind and current, although at best the docking will be sloppy, but even the finest tugs do not make it possible to fight a strong wind or current. Nor is it necessary for them to be asked to.
Before starting the docking get out on the bridge wing and feel the wind and weather on your face. Look up at the stack and down at the water. Look out to the horizon and check what the future weather conditions might be. Constant awareness of wind, weather, and current is effective shiphandling.
A 30-knot wind exerts the same force on an equal area as a I-knot current. This ratio is altered by variables such as the surface area of the superstructure, the ratio of the ship's draft to her freeboard, and the vessel's trim.
As a ship's speed is reduced, the momentum of the ship and the effectiveness of her rudder and engine decrease while the wind and current remain the same. When the ship is dead in the water, only the wind and current act upon her, although at some prior point these outside forces have become dominant. If the docking has been properly planned, the ship is so positioned that as the wind and current take charge they assist the shiphandler in docking the vessel. The ship's angle of approach and speed are adjusted to compensate for wind and current, and anchors and tugs are used as necessary.
Let's look at some of the ways in which the wind and current may assist the ship:
1. A wind blowing off the berth can be used to overcome a ship's lateral motion toward that berth, instead of using the tugs and engine.
2. A wind blowing on the berth can ease a ship alongside if the shiphandler stops her a few feet oft' the berth.
Don't fight a strong wind, let the ship go alongside and slide up the stringpiece into position, The ship can't be blown heavily against the dock after stopping in position if she is already alongside. These are a couple examples of ways in which you can use wind and current as tools rather than allowing them to become problems.
