McCawley - class attack transport The " McCawley " - class attack transport was a class of US Navy attack transport that saw service in World War II . Like all attack transports , the purpose of the " McCawley " - class ships was to transport troops and their equipment to hostile shores in order to execute amphibious invasions . Attack transports carried a substantial number of integral landing craft for making the assault , and were well armed with antiaircraft weaponry to protect themselves and their vulnerable cargo of troops from air attack in the battle zone . Background . The " McCawley " class is amongst the few classes of attack transport that were converted from pre - war tonnage rather than being built during the war from either Maritime Commission or Victory ship hull types . The two ships of this class also hold the distinction of being the only attack transports not to be built in the United States . The origin of the two ships which were to become the " McCawley " class goes back to a United States government decision in the 1920s that allowed foreign - built ships to retain eligibility for US mail contracts . Accordingly , the American shipping company Grace Lines ordered two cargo liners from the Furness Shipbuilding Company of Haverton Hill - on - Tees in Northern England , which were completed in 1928 as " Santa Barbara " and " Santa Maria " . These ships were the first large diesel - powered passenger ships to sail under the American flag . The two Grace Lines ships continued to operate between the United States and South America , and later on US coastal mail runs , until being bought by the US Navy for conversion to troop transport s in late 1940 . The conversions were duly carried out , and " Santa Barbara " and " Santa Maria " became USS " McCawley " ( AP - 10 ) and USS " Barnett " ( AP - 11 ) respectively . They were reclassified as attack transports APA - 4 and APA - 5 on 1 February 1943 . Description . The " McCawley " s were each powered by two eight - cylinder , two - cycle , diesel engines yielding a total horsepower of 8000 and a top speed of around . In commercial service they carried 150 passengers and had a gross tonnage of 8000 . After conversion to attack transports , they had a troop capacity of about 1 , 300 and a cargo capacity of about . They were each armed with four 3 " / 50 caliber dual - purpose guns and a variable assortment of secondary armament . In service . Both ships saw their first action in the long and bitterly fought Guadalcanal campaign in the Pacific Theatre . Sadly , this would prove to be " McCawley " ' s one and only campaign . After participating in the initial landings in August 1942 as the command ship of Admiral Richmond K . Turner , and continuing in support missions to the island for the next nine months , she was mistaken for an enemy vessel by US Navy MTB s on the night of 30 June 1943 and sunk by torpedoes . Her sister ship , " Barnett " , survived the Guadalcanal campaign and went on to take part in most of the major amphibious operations in the European Theatre , including the invasions of Sicily , Italy , Normandy and Southern France , before returning to the Pacific to participate in the invasion of Okinawa in 1945 . " Barnett " was decommissioned along with most other attack transports in early 1946 , and sold into commercial service not long thereafter .