 The revised Combined Operations plan required one destroyer to ram the dock gates and a number of smaller craft to transport the Commandos . The Royal Navy would therefore provide the largest contingent for the raid , under the overall command of the senior naval officer , Commander Robert Ryder . The ship selected to ram into the dock gates was HMS Campbeltown , commanded by Lieutenant Commander Stephen <unk> Beattie . Campbeltown was a First World War destroyer and had previously been the USS Buchanan in the United States Navy . She had come into RN service in 1940 as one of 50 destroyers transferred to the United Kingdom under the Destroyers for <unk> Agreement . 
