The paper describes our involvement in the high court reopened formal investigation into the sinking of the bulk carrier M. V. Derbyshire. The statistical problem that we addressed concerned the estimation of the probability that the ship had sunk from a particular form of structural failure, resulting from large wave impacts on the ship, for each of a range of possible sea-state and vessel conditions. We considered several statistical models for the wave impacts on the ship with the generalized Pareto distribution, motivated by extreme value theory, providing an excellent description and aiding the investigation to draw clear conclusions about the cause of the sinking.