Numerical assessment of factors affecting the survivability of damaged ro–ro ships in waves

A mathematical model in the time domain of the motions and flooding of ships in a seaway is described. This model is applied to the numerical simulation of the behaviour of a damaged ro–ro ship in waves. The effects of parametric variations of different factors in the ship's survivability are asessed. Numerical results are given for a passenger ro–ro ship, which is studied in a damage condition that includes the main engine room. The permeability of this room is taken in consideration by modeling the engines as intact blocks inside the engine room. The ship's survivability in irregular waves is then calculated for different variations in the following parameters: vertical location of the centre of gravity, spectral description of the seaway, roll damping factor, discharge coefficients, depth to main deck, double-hull in the main deck and initial heel angle. The transient effects associated with complicated damage condition geometries and the floodwater effects on roll motion are also assessed. The results are discussed and conclusions drawn.