The boxed aircraft transports was a redesign of the basic Liberty Ship. But with the aircraft transports four hatches, two forward and two aft, replaced the the customary five that was found on the standard Liberty Ship. The size of the hatches was also increased. Three hatches were 23' x 42'6" and the fourth was 20' x 20'.
Instead of the standard three masts, the masting was arranged to handle loads up to 30 tons, and this involved the fitting of four goal type masts, one set forward of each hatch and a pair of king post fitted to the bridge front. Two 30 ton and two 15 ton cargo booms were located at each hatch, while No 4 hatch was equipped with two 5 ton derricks.
Forty vessels of this type was ordered and the first one was delivered in January of 1945. Others followed during the following 10 months, but by the latter part of this period the need for the vessels had faded. Only thirty six were delivered and the remaining four contracts were canceled.
NOTE: The above information was attained from the book "The Liberty Ships" by L. A. Sawyer and W.H. Mitchell