Wednesday, December 5, 2007

SHIP HANDLING (CURRENT ASTERN)

APPROACHING A WHARF-CURRENT ASTERN
Docking at a wharf with the current running from astern requires greater planning and skill. The ship comes up to the berth with the intent of backing into position since she will be making sternway through the water when stopped in position relative to the wharf. If the ship handler thinks of the job in this way, that the ship is coming stern first into the current to the berth, the maneuver becomes much more straightforward.
Come abeam of the assigned berth with two tugs made fast and take all headway off the ship. Continue backing the engine while keeping the stern angled slightly toward the wharf and, as the ship gains stern­way through the water (while stopped or nearly stopped relative to the bottom), the current on the ship's offshore side moves her laterally toward the wharf. Use only enough speed to hold the ship in position and use the tugs as required to control the ship as she is set alongside by the current.

Once alongside, the tugs hold the ship against the eddy current that exists at the wharf. The mate on the stern must keep the propeller clear while running stern lines since the engine is used continuously to hold the ship in position against the current. The tugs can also help to hold the ship in position by keeping an angle into the current rather than being at right angles to the ship's hull. Their thrust holds the ship alongside and up to the current.

Berthing with the current from astern is not a problem so long as it is kept in mind that the ship is effectively backing stern first into posi­tion. By adjusting the angle that the ship makes to the current, stern toward the dock to move in that direction, stern parallel to the dock to check the lateral motion toward the pier or move away from it, the ship can be safely berthed. Any problems that arise when docking with the current from astern usually result from trying to push the ship alongside with the tugs, rather than letting the current set the ship onto the berth. The vessel gets away from the ship handler because the current takes charge. Use the tugs only to assist to keep the needed angle as the ship is set alongside.