On December 7, 1966, the passenger ferry SS HERAKLION sank close to the Greek island Milos. The cargo on the vehicle deck was not correctly lashed, especially one reefer truck which was taken on board prior to the departure in the port of Chania. The HERAKLON sailed in strong stern quartering seas and wind of abt. 8-10 BFT. Due to the (parametric) rolling motion cargo shifted, and the unsecured reefer truck pushed the side door to the vehicle deck open. Water accumulated on the vehicle deck, and the static list increased until the vehicle deck became fully submerged. The vessel then capsized rapidly and sank, as water could spread into the ship through unsecured openings. Only 46 of 264 persons could be saved. The accident may be the first accident where floodwater on the vehicle deck played a major role. Our simulation shows the sinking sequence (without seakeeping motions) after the vehicle deck was submerged.