This was a deliberate Navy design directive, as previous wartime transport losses emphasized the risks of having too many troops and large quantities of cargo in a single hull.

There were other advantages to a smaller transport design as well; a reduction in draft allowed for more flexibility in shallow approaches, less time was required for offloading, and having a greater number of small ships distributed troops and materials more evenly across the assault line.

Originally the class was to be only 380' in length, but the design had to be enlarged to accommodate a turbo-electric propulsion plant (which was the only machinery readily obtainable by the Maritime Commission at the time).

In the immediate postwar period, the Gilliams, like most other classes of attack transport, were initially utilized to transport US troops for occupation duties - in Japan, China, Korea and other Far Eastern locations formerly occupied by the Imperial Japanese Army - and later as participants in Operation Magic Carpet, the giant sealift organized to bring hundreds of thousands of demobilizing soldiers back to the United States.

Known as Operation Crossroads, these tests were to be conducted on a large array of unmanned target ships to determine the effects of atomic explosions on a variety of vessel types.

The Gilliams were identified as being well-suited to the tests, not because of any perceived inferiority or lack of value (they were in fact relatively new, well-constructed vessels) but rather because they were designed with an exclusive wartime function in mind and had little adaptability to other roles.

The need for these specialized attack transports had largely evaporated, and because their cargo carrying capacity and endurance was limited the Maritime Commission had no use for them in the peacetime merchant fleet.

In all likelihood Appling would have been obliterated in the blast, but fate saw that she was returned to the United States and laid up along with the remainder of her sisters who either survived or avoided the tests.

Serious consideration was later given to utilizing the ships as mobile power-generating stations, as their turbo-electric plant was seen as their biggest asset and was capable of generating a significant amount of electricity.