On the Towing of Damaged Ships : 3rd Report Ship Motion and Wave Drift Force of Various Kinds of Ships

Abstract

The authors developed the computer system named optimum towing support system (OTSS) which can predict the drift motion, towline force, maneuvering method and needed horse power of the tow ship. The purpose of this research is to establish the techniques to prevent disabled ships from drifting and to tow them to the safety area in rough sea in order to prevent the secondary disaster such as collision, distress and explosion. There are 7 ship types including 2 kinds of tankers in the system. The hydrodynamic force acting on the disabled ships is calculated using 3 dimensional panel method in the OTSS system. The various ship status conditions such as capsize and breakage can be simulated. The hydrodynamic force of the tow and towed ship can be calculated in the computer system of OTSS. The motion and wave drift force of damaged and broken ships of various types in waves were calculated using OTSS in this report. The numerical calculation on the capsized condition was also done. The behavior of towed ships during towing was investigated. The numerical calculation was compared with the past experimental results concerning the broken tanker like 'Nakhodka'.