The Gilliam-class attack transport was a class of attack transport built for service with the US Navy in World War II. Like all attack transports, the purpose of the Gilliams was to transport troops and equipment to foreign shores in order to execute amphibious invasions using an array of smaller amphibious assault boats carried by the attack transport itself. The Gilliam-class was heavily armed with antiaircraft weaponry to protect itself and its cargo of troops from air attack in the battle zone. History The Gilliam-class was designed by San Francisco naval architects Joslyn & Ryan and designated by the Maritime Commission (MARCOM) as type S4-SE2-BD1. The Gilliams were significantly smaller, both in size and displacement, than other classes of attack transports. 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. In particular, the Navy cited the loss of the during the Guadalcanal campaign as an example of this. The vulnerability of large transports was later reinforced by the costly loss of five combat loaded AP's during the Invasion of North Africa. 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. Achieving the design goal of 15 knots speed with no more than 15 feet of draft, with capacity for 600 troops and 60,000 cubic feet of cargo required that the Gilliams be constructed as lightly as possible. 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). The final design yielded a twin-screw vessel capable of 16.5 knots with a maximum draft of 15.5', an overall length of 426' and a troop-carrying capacity of 800. A distinctive feature of the ships was the sharply raked "Meierform" bow which helped to reduce pitching in heavy seas. The turbo-electric propulsion system was also seen as innovative for a vessel of this type and proved to be reliable in service. Closely related to the original BD1 design were the Type S4 attack cargo ships, the class, which were designated