Bayfield - class attack transport The " Bayfield " - class attack transport was a class of US Navy attack transport s that were built during World War II . With the entry of the United States into the war , it was quickly realized that amphibious combat operations on hostile shores would be required , and that specialized ships would be needed for the purpose . The so - called " attack transport " ship type ( hull classification symbol " APA " ) was developed to meet this need . Attack transports were converted from standard transport vessels by being upgraded with extra firepower , and outfitted with a number of smaller integral landing craft ( such as LCVP s and LCM s ) with which amphibious assaults could be conducted . The first attack transports began to enter service in 1942 and were built ad hoc from a host of different types . The first class of attack transports to be built in substantial numbers was the " Bayfield " class which began to enter service in 1943 . The early " Bayfield " - class vessels were converted from existing cargo or transport ships , later ones were built as attack transports from scratch . Overview . " Bayfield " - class vessels were based on the large Type C3 passenger and cargo ship standard set by the US Maritime Commission . Originating in 1938 , The C3 standard was designed to produce modern , good quality cargo and passenger ships to replace the ageing US merchant fleet , and which could also be readily converted into naval auxiliary vessels in the event of war . After the war broke out however , the need for shipping became so great that the US was forced to come up with designs that could be more quickly manufactured . Thus the C3 - based " Bayfield " class and its predecessors were eventually outnumbered by the which was based on the simpler Victory ship design . Description . " Bayfield " - class vessels were based upon the C3 - S - A2 design standard . The basic design had to undergo a number of changes in order to meet the attack transport specification . Troop accommodation . In order to accommodate the troops , two cargo holds amidships had to be converted into accommodation facilities . This was achieved by dividing each hold into three decks , and then building a number of passageways along each deck . Along both walls of each passageway , bunk - beds tiered five high were installed , and since space was still at a premium , each bunk was only thirty inches wide . The troops were provided with their own galley and mess hall separate from that of the ship ' s crew , but they had no dining hall and used their own mess gear to eat . A sick bay and dental clinic were also provided . The troop commander had his own private cabin and office , which was fitted with a loudspeaker system from which he could directly address the men under his command . In order to keep the soldiers entertained during their long , crowded voyages , music and other entertainment could be piped to the troop compartments . Ballast . Because a troop transport carries less weight than a cargo ship , it was also found to be useful to place concrete in the bottom of the cargo holds in order to improve the ship ' s comfort , safety and performance . Weaponry . Since attack transports would be conducting operations off hostile shores , they had a greater requirement for armament than ordinary transports , particularly in regards to antiaircraft defence . The " Bayfield " class vessels were well outfitted in this regard . Each vessel was fitted with a pair of 5 " / 38 calibre dual purpose guns , one fore and one aft . The ships were also fitted with between two and four twin 40mm antiaircraft mounts ( early examples came with two quad 1 . 1 " gun mounts instead ) , plus two single 40 mm mounts and eighteen 20mm mounts as standard . As the war progressed , the 20 mm cannon were found to be less effective than the 40 mm , and the later " Gilliam " and " Haskell " classes dispensed with some of these mounts . The later classes also had only one gun instead of two . Production . A total of 34 " Bayfield " - class vessels were produced between 1942 and 1944 - 20 by Ingalls Shipbuilding of Pascagoula , Mississippi and the remaining 14 at the San Francisco shipyard of Western Pipe & Steel - making the " Bayfield " class the second most numerous attack transport class behind the " Haskell " class . Service . " Bayfield " - class vessels served in both the Atlantic and Pacific theatre s of war . Some went on to see service in the Korean and Vietnam war s . Of the 388 attack transports ( APA and AKA ) of all types built , the last to see service with the US Navy was the , a " Bayfield " - class vessel built by Western Pipe & Steel which was launched on 29 December 1942 , first commissioned on 7 December 1943 and decommissioned in August 1970 . She was finally struck from the Navy register on 1 July 1972 .