On 2 July 1940, the ocean liner SS Arandora Star was torpedoed and sunk by German submarine U-47, with the loss of around 805 lives; over half of these were British-Italian civilian internees. This article approaches the event from the arena of Second World War military history, contextualising the sinking within the early Battle of the Atlantic. In so doing, it shifts the customary focus away from government internment policy and discussions of cultural legacy towards examining British and German naval strategies and realities. Tactical and logistical considerations of the conflict are investigated, the explication of which allows more detailed discussion of the sinking controversies and enables delivery of ‘answers’ to the persistent ‘questions’ of why Arandora Star was sailing unescorted and without Red Cross insignia. The broad perspective offered engages with transgression and culpability, and overall the article seeks to advance Arandora Star scholarship with its distinctive maritime focus.