On the effects of non-watertight doors on progressive flooding in a damaged passenger ship

The intermediate stages of flooding can be very dangerous, especially if the flooding is asymmetric. Modern passenger ships have complex transverse and vertical subdivisions inside the watertight compartments. These structures are often needed for fire integrity, and they are not watertight. However, in the event of damage they may have a significant effect on the flooding process. Time-domain flooding simulation, combined with the latest research on the leakage and collapse of non-watertight structures, enables a very realistic approach on the intermediate phases of flooding. In this paper the effects of random variation in the status of the fire doors (open or closed) and the applied parameters for modelling leaking and collapsing of closed non-watertight doors are studied. The results indicate that the status of a non-watertight door can have enormous effects on the progress of flooding, and especially on the time-to-capsize. On the other hand, variation in the modelling of leakage and collapse parameters' of closed doors had much smaller effects. The results can be utilized in planning a conservative combination of non-watertight door statuses in time-domain damage stability analysis for ship design, and in the assessment of uncertainty of the results from such computations.