Just after 11:00 on 16 January, 1914, and commanded by Lt. Gilbert Welman, the A7 began her simulated attack on the Pigmy. However, after diving, nothing more was seen of the boat. Over an hour after the exercise started, crew members of the Pigmy saw bubbles on the surface, suggesting that the submarine was attempting to blow water from her ballast tanks in an attempt to rise (the lack of adequate reserve buoyancy was noted as one of the A class’s major design shortcomings). The location was marked with a buoy before the Pigmy returned to Devonport to report the incident. Unfortunately, there was only enough air in the submarine for six hours and, tragically, all 11 crew members perished. Despite numerous salvage attempts over the following month, the A7 refused to move and so it was decided the leave her where she lay, in about 135ft of water. In 2001, she was declared as a "Controlled Sites" under the British Government’s Protection of Military Remains Act 1986 (Designation of Vessels and Controlled Sites), which means that diving on her is prohibited without special permission from the MoD.