this training ship was moored on the river hamble, near southampton, hampshire, and had a dormitory ship called hms "president" that had previously been . the commander of the "mercury" training site was the cricketer c. b. fry, and choules' time there included trips to netley hospital as part of the "mercury"s dancing team. the examinations taken by choules following his training on the "mercury" qualified him to attend the advanced class on the naval training ship hms "impregnable" situated at the devonport naval base in plymouth. choules transferred there on 10 october 1916, for what was to be the final stage of his training before joining the royal navy's grand fleet.