Strength of Catamaran Ship : 3rd Report : Wave Induced Stresses Acting on Connecting Deck

Abstract

The catamaran ship has twin hulls and a connecting desk. Stiffness of the deck is generally very small compared with that of each hull. Therefore, to analyze motions of ocean going catamaran ship in waves, effect of elastic deformation of the deck can not be neglected. In the 1st report, considering forces and moments acting in the connecting deck induced by the relative motions of the twin hulls, motions of each hull in waves were analyzed. And it was found that loads acting in the deck due to relative motions of the twin hulls became largest in the transverse waves and effect of hydrodynamic interaction between twin hulls could not be neglected. In the 2nd report, considering the hydrodynamic interaction between twin hulls and the elastic deformation of the deck, motions of each hull in the transverse and oblique waves were analyzed and the loads acting in the deck due to relative motions of the twin hulls were investigated. The connecting deck is acted by two kinds of wave induced stresses. The one is the stress by elastic deformation of the deck due to relative motions of the twin hulls. The other is the stress by elastic deformation of hull structure and the deck due to dynamic pressure and inertia force acting on the ship induced by motions of the twin hulls in the waves. In this report, those wave induced stresses acting in the deck were analyzed and effect of scantling and stiffness of the connecting deck and the twin hulls on the stresses in the deck were investigated.