Editing Sargo-class submarine (section)

==Design==

In most features the ''Sargo''s were a repeat of the ''Salmon''s, except for the return to full [[diesel-electric]] drive for the last four boats and the adoption of the improved ''Sargo'' [[battery (electricity)|battery]] design. The first six ''Sargo''s were driven by a composite [[direct drive|direct-drive]] and diesel-electric plant (two engines in each mode) in the same manner as the ''Salmon''s.  In this arrangement, two main engines in the forward engine room drove [[electric generator|generators]]. In the after engine room, two side-by-side engines were clutched to [[gear|reduction gears]] which sat forward of the engines, with vibration-isolating hydraulic clutches. Two high-speed [[electric motor]]s, driven by the generating engines or batteries, were also connected to each reduction gear.<ref>Friedman, p. 203</ref> The [[Bureau of Steam Engineering]] (BuEng) and the [[General Board of the United States Navy|General Board]] desired a full diesel-electric plant, but there were some dissenting opinions, notably Admiral [[Thomas C. Hart]], the only experienced submariner on the General Board, who pointed out that a full diesel-electric system could be disabled by flooding.<ref name="Friedman, p. 204">Friedman, p. 204</ref> Technical problems went against the use of two large [[direct drive|direct-drive]] diesels in place of the four-engine composite plant. No engine of suitable power to reach the desired 21-knot speed existed in the US, and the current vibration-isolating hydraulic clutches were not capable of transmitting enough power. It was also not practical to gear two engines to each shaft.<ref name="Friedman, p. 204"/> So a full diesel-electric plant was adopted for the last four ''Sargo''s, and remained standard for all subsequent conventionally-powered US submarines.

Four of the class (''Sargo'', ''Saury'', ''Spearfish'', and ''Seadragon'') were equipped with the troublesome [[Hooven-Owens-Rentschler]] (HOR) [[double-acting cylinder|double-acting]] diesels. An attempt to produce more power from a smaller engine than other contemporary designs, the double-acting system proved unreliable in service. During [[World War II]], all had their engines replaced with [[General Motors|GM]] [[Cleveland Diesel]] 16-278A engines, probably during their overhauls in early 1943.<ref>Friedman, pp. 263, 360-361</ref>

BuEng had designed a new [[lead-acid battery]] to resist battle damage, known as the ''Sargo'' battery because it was first installed on {{USS|Sargo|SS-188|2}} and was based on a suggestion by her commissioning [[commanding officer]], Lieutenant E. E. Yeomans.<ref>Friedman, p. 265</ref> Instead of a single hard rubber case, it had two concentric hard rubber cases with a layer of soft rubber between them. This was to prevent [[sulfuric acid]] leakage in the event one case cracked during [[depth charge|depth-charging]].<ref>[http://pwencycl.kgbudge.com/S/a/Sargo_class.htm The Pacific War Online Encyclopedia, ''Sargo''-class article]</ref> This remained the standard battery design until replaced with Sargo II and GUPPY batteries in submarines upgraded under the [[Greater Underwater Propulsion Power Program]] after [[World War II]]. Each battery's capacity was slightly increased by installing 126 [[electrochemical cell|cells]] instead of 120; this also raised the nominal voltage from 250 [[volt]]s to 270 volts, which has been standard in US usage ever since, including the backup batteries of [[nuclear submarine]]s.

The original Mark 21 [[3"/50 caliber gun|3-inch (76 mm)/50 caliber]] [[deck gun]] proved to be too light in service. It lacked sufficient punch to finish off crippled or small targets quickly enough to suit the crews. It was replaced by the Mark 9 [[4"/50 caliber gun|4-inch (102 mm)/50 caliber gun]] in 1943-44, in most cases removed from an [[United States S-class submarine|S-boat]] being transferred to training duty.<ref>Alden, p.93.</ref>