was on optimizing underwater performance, and thus the boats had very little superstructure topside and a very small conning tower. Since these boats were intended for harbor defense and would be operating in relatively calm waters, this was not initially considered a problem. They were not internally subdivided, there was essentially one large compartment from bow to stern. One man, a very busy Commanding Officer, stood on a raised platform amidships with his head up inside the conning tower so he could see out of the small deadlight windows there. Initially there were no periscopes. Several wheels and control levers were within reach of this station, with the Commanding Officer acting as both a helmsman and a diving plane operator. He kept track of his bearings and any potential target by periodically broaching the boat so he could see out of the deadlights. The designed test depth was 100 feet, although Porpoise survived an accidental grounding at 144 feet in 1904. Builder's and Navy trials of the class noted several defects that needed to be corrected. Ventilation of the gasoline engine was poor, the main switchboard needed to be relocated, the 30-foot depth gauge was inadequate, the torpedo tube muzzle door was awkward to use, and periscopes were highly desired. Most notably, the lack of superstructure and the short conning tower made these boats prone to flooding when surfaced in even a moderate sea state. A modification program was drawn up and approved by the Navy and starting in January, 1905 the boats were taken in hand for the needed work. Eventually most of the boats were fitted with two fixed height periscopes, with a taller conning tower that had a large fairwater built around it. A removeable bow fairing was put in place to increase seaworthiness, helping to push the bow wake away from the conning tower. Since the boats found themselves spending more time on the surface than originally thought, a surface steering station was added forward of the conning tower fairwater, connected by a shaft to the main steering mechanism below. A small, metal framework and canvas bridge structure could be erected topside for extended surface transits. It had to be disassembled and taken below before diving. The diving process was quite lengthy and complicated, taking several minutes from being fully surfaced to fully submerged. The tactical environment that these boats operated in did not necessitate quick