"Adventure" was built to replace the converted First World War veteran "Princess Margaret", and her design was dictated by a requirement for a large mine capacity and a good cruising range. The mineload was to be carried completely internally, dictating a long, tall hull, and there were four sets of rails running the length of the hull to chutes at the stern. She was built with a transom, or flat, stern, to improve cruising efficiency, but the dead water caused by such a form meant that mines tended to be sucked back into the hull when they were launched; an obviously dangerous situation for a minelayer. As a result, she was rebuilt with a traditional cruiser, or rounded, stern, increasing the length by .