Parametric Formulation of the Floodable Length Curve: Application Case to Offshore Patrol Vessels

The residual buoyancy of vessels after damage has a fundamental role in their survivability and it is implemented through adequate ship internal subdivision. Traditionally the number and the position of transverse watertight bulkheads are selected for most ships early in the design phase by means of the “floodable length curve” coupled with the concept of “margin line”. However, for naval vessels, it is more and more common during the acquisition process to explore a wide domain of feasible ships, identified with the assistance of automated processes and assessed also in terms of capabilities, among which is survivability. The generation and the comparison of a considerable number of different ship configurations is very time consuming. Therefore recourse to a parametric expression of the floodable length curve is considered to be a very efficient approach and would thus enable characterisation of the ship, in terms of survivability performance. In this paper such an approach is presented, using an offshore patrol vessel (OPV) as the case study.