Editing Plunger-class submarine (section)

== Design and construction ==

These boats were essentially an enlarged and improved version of the [[USS Holland (SS-1)|''Holland'']], with a much more powerful 4-cylinder, 160 bhp [[Otto engine]] and an enlarged battery. Their increased size allowed a crewman to stand upright inside the boat. They were designed by [[General Dynamics Electric Boat|Electric Boat]] under the direct supervision of [[John Philip Holland]] and were known to the company as design EB 7.<ref>Friedman, pp. 27 & 29</ref> The design was considered such an advance over the ''Holland'' that the company took the unusual step of ordering a prototype of the class using internal company funds. The prototype, named ''Fulton'', was built at [[Lewis Nixon (naval architect)|Lewis Nixon]]'s [[Crescent Shipyard]] in [[New Jersey]]. It was a fortunate move, as the ''Fulton's'' company trials turned up numerous deficiencies that needed to be corrected. These trials, along with the need to correct the noted deficiencies delayed the building of the ''Plungers''. On average the boats were delivered to the Navy two years late.<ref>Friedman, pp. 27-28</ref> Although ''Fulton'' eventually did quite well on trials, proving the capabilities of the ''Plungers'', there were no approved appropriations from the Navy to purchase her so she was sold to [[Russian Navy|Russia]], and renamed {{sclass|Som|submarine|5}}.

A single hull design, all ballast and fuel tanks were located internally. The battery had 66 cells located underneath the torpedo reloads and was 24% more powerful than the one installed on ''Holland''. The battery was open-topped, and when the decking was removed the battery acid could be seen sloshing around inside the cells. The top was shellacked wooden planks, with a layer of rubber above and finally a shellacked canvas covering.<ref>Christley, pp. 10</ref><ref name="PigBoats.COM A-boat Page">[https://pigboats.com/index.php?title=A-class PigBoats.COM A-class page]</ref> Holland's emphasis 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 [[periscope]]s. 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 [[USS Porpoise (SS-7)|''Porpoise'']] survived an accidental grounding at 144 feet in 1904.<ref>Friedman, pp. 28-30</ref>

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.<ref>Friedman, pp. 30, 32-35</ref> Eventually most of the boats were fitted with two fixed height periscopes, with a taller conning tower that had a large [[Fairing (nautical)|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.<ref>Friedman, pp. 37</ref><ref name="PigBoats.COM A-boat Page"/> The diving process was quite lengthy and complicated, taking several minutes from being fully surfaced to fully submerged.<ref>Friedman, pp. 30</ref> The tactical environment that these boats operated in did not necessitate quick dives, thus the lengthy dive process was not seen as a liability.
   
At this point in their corporate history, Electric Boat was a design and engineering firm only. They did not have their own shipyard and thus sub-contracted out the construction of all their boats. The ''Plunger'' class was built at two different locations on both coasts of the United States. Five were built at the Crescent Shipyard in Elizabethport, New Jersey, while two more were built at [[Union Iron Works]] in [[San Francisco]].