According to Konopelko (1990), damages to the hull occur in 53% of ships’ accidents. On average, each ship of the world fleet suffers hull damage once in 10 years with two ships out of one hundred damaged ships being lost. More updated statistics on ship losses can be found in Guedes Soares and Teixeira (2001).
A great variety of incidents exist, such as collisions, grounding, explosions and fires, severe storms, etc. Therefore, a great variety of hull structure damages exist as well. An example of classification of hull damages after collision is given in Table 1, related to MV "Mozdok" (Egorov, 2006a).
Besides holes, there are many damages of the hull that can be identified, such as rupture of elements (infringement of integrity of a hull structure element due to exhaustion of its plastic deformation limit), cracks (infringement of integrity of a hull structure element due to fatigue) or one-time overload in area of indents or bulges resulting from buckling, as well as different kinds of deformations that are observed after accident (Egorov 2007).
The following types of residual deformations can be defined (see Fig. 1): indentions (local plate permanent deflection in some areas between stiffeners); corrugation (permanent deflections of several adjacent areas of plate between stiffeners); dents (local permanent deflection of a panel, which includes the plate and supporting stiffeners); bulge (permanent deflection of the stiffener‘s web plate or the stiffener’s attached plate)