Surendran Sankunny

The prediction of ship stability during the early stages of design is very important from the point of vessel's safety. Out of the six motions of a ship, the critical motion leading to capsize of a vessel is the rolling motion. In the present study, particular attention is paid to the performance of a ship in beam sea. The linear ship response in waves is evaluated using strip theory. Critical condition in the rolling motion of a ship is when it is subjected to synchronous beam waves. In this paper, a nonlinear approach has been tried to predict the roll response of a vessel. Various representations of damping and restoring terms found in the literature are investigated. A parametric investigation is undertaken to identify the effect of a number of key parameters like wave amplitude, wave frequency, metacentric height, etc. © 2002 Elsevier Science Ltd. All rights reserved.

Handling of heavy structures demand unusual crane capacity. Availability of such cranes may be limited in developing countries. An innovative way to construct and launch heavy concrete structures in a developing country, where crane availability is rare, to lift, transport and handle heavy structures, is discussed in this paper. Heavy caissons are used in the marine environment as breakwaters, as berthing facilities for vessels, as gravity structures to absorb energy from waves, etc. The methodology for constructing multi-caissons on-board a barge and then on-board a floating dock is the subject of this paper. The respective feasibilities are discussed. The free floating condition of the caisson and its righting arm stability are described. At first the caisson was considered as its lip wall opened to the sea. The case of lip wall closed for more bouyancy is also considered. The stability of the barge and floating docks is shown for various stages of completion of construction. After investigating many factors, a safe procedure for construction and launching thereafter is described in this paper. The problem of handling a heavy concrete structure from the view point of a naval architect is highlighted.