When the Royal Navy produced a mine that could be laid from a 21-inch torpedo tube, the need for specialized submarine minelayers disappeared. Surprisingly, the introduction of this newly-designed mine did not lead to the redundancy of existing minelayers, and these purpose-built vessels proved extremely successful in the Second World War when used as supply. submarines, running precious cargoes to Malta in 1941 and 1942. Their spacious mine-decks were filled with such diverse items as machine-gun ammunition, glycol coolant for Spitfires, and food.
