Open AccessTHE STUDY OF SHIPS BEHAVIOR DURING PORT MANEUVERING WITH TUGS
Author(s) -
Alecu Toma
Publication year - 2016
Publication title -
scientific bulletin
Language(s) - English
Resource type - Journals
eISSN - 2392-8956
pISSN - 1454-864X
DOI - 10.21279/1454-864x-16-i2-017
Subject(s) - port (circuit theory) , marine engineering , engineering , aeronautics , environmental science , electrical engineering
Most of the time, during the turning, the motion of the ship is not a perfect circle because there are several forces acting on the ship and these forces change continuously. In this paper we study the real motion of the ship when a transverse force is applied by a tug at the different points of the moving or stationary ship. The pivot point is useful by seafarers to visualise the rotation of a ship during its combined rotation/translation movement. It is the result of all forces acting on the ship and its position changes continuously during the ship’s displacement, depending on the forces involved.The centre of drift is the point at which the resultant of all hydrodynamic forces acts: underwater resistance, lift and drag as a function of speed and drift angle. The underwater resistance force exists both for pure headway or sternway motion and for all lateral motions. It induces flow velocities below and beside the hull. On a real turning circle the heading is not completely constant as it undergoes small variations due to small changes in the forces acting on the ship: local variations in water depth, variations in distance from the shore line, local currents or wind gusts.