USS Frederick (LST-1184) was a which replaced the traditional bow door-design tank landing ships (LSTs) of the United States Navy. The ship was named after the city of Frederick, Maryland and Frederick County, Maryland. The vessel entered service in 1970 with the United States Pacific Fleet and saw service during the Vietnam War, and the Persian Gulf War earning three battle stars. The ship was decommissioned in 2002 and put up for sale. Frederick was acquired by the Mexican Navy the same year as part of the Security Assistance Program and entered service in December 2002 renamed ARM Usumacinta. Usumacinta has since taken part in three RIMPAC multi-national naval exercises as well as provide humanitarian support following earthquakes in Oaxaca and Chiapas. Design and description Frederick was a which were designed to meet the goal put forward by the United States amphibious forces to have a tank landing ship (LST) capable of over . However, the traditional bow door form for LSTs would not be capable. Therefore, the designers of the Newport class came up with a design of a traditional ship hull with a aluminum ramp slung over the bow supported by two derrick arms. The ramp was capable of sustaining loads up to . This made the Newport class the first to depart from the standard LST design that had been developed in early World War II. Frederick had a displacement of when light and at full load. The LST was long overall and over the derrick arms which protruded past the bow. The vessel had a beam of , a draft forward of and at the stern at full load. Frederick was fitted with six Alco 251-C diesel engines turning two shafts, three to each shaft. The system was rated at and gave the ship a maximum speed of for short periods and could only sustain for an extended length of time. The LST carried of diesel fuel for a range of at the cruising speed of . The ship was also equipped with a bow thruster to allow for better maneuvering near causeways and to hold position while offshore during the unloading of amphibious vehicles. The Newport class were larger and faster than previous LSTs and were able to transport tanks, heavy vehicles and engineer groups and supplies that were too large for helicopters or smaller landing craft to carry. The LSTs have a ramp forward