Littoral Combat Ships (LCSs) are the new entry into the United States Navy (USN) ranks. These warships represent vessels of relatively combat size intended to operate near the shoreline in support of amphibious operations, taking on patrol roles, or used as deterrents. Compared to existing naval ship types, they mostly resemble corvettes or frigates in capability. They are also Blue Water capable allowing the type to journey beyond shorelines and shallow waterways (the "littoral zone").
The Navy approved two distinct LCS designs which became the Freedom-class and the Independence-class. USS St. Louis belongs to the Freedom-class portion of the littoral combat ship fleet developed by defense industry powerhouse Lockheed Martin. The class has a more traditional, single-hull design approach than its Independence-class sisters which utilized a trimaran hull arrangement (this class is detailed elsewhere on this site). Nineteen of these warships, developed by Austal USA, were originally planned and, as of this writing, seven are in active service.
The Freedom-class, with fifteen ships planned, has seen six of their kind completed (2018) with seven under construction and two still on order.
The warship's silhouette is all-modern with slab-siding and shrouded protrusions. The forecastle has few obstructions with the major component being a single turreted deck gun. The mass of the ship is at midships with the bridge and hangar sections integrated into the hull superstructure. Atop this structure is the main mast containing the various communications, sensors, and radar fits. The smoke funnels are of a very-low-profile design and also integrated into the superstructure. The hanger section makes up the aft-part of the structure. This leads out to the helipad.
Displacement of the design reaches nearly 4,000 tons under full load. Dimensions include an overall-length of 378 feet, a beam of 57 feet and a draught down to 13 feet. The latter measurement is of note for it supplies the warship with the needed shallow draught to take part in close-to-shore operations.
Power to the warship is from 2 x Rolls-Royce MT30 gas turbines coupled with 2 x Colt-Pielstick marine diesel engines allowing the warship to hit maximum speeds of 45 knots and range out to 3,500 nautical miles (when cruising at 18 knots). 4 x Rolls-Royce waterjets supply fine-maneuvering capabilities.
The warship relies on a base operating crew of about fifty personnel (it can operate with as few as fifteen) and has a Blue and Gold mission crew numbering seventy-five. The ship's endurance is approximately twenty-one days at sea before requiring a complete resupply.
Aboard are several 40-foot Rigid-Hull Inflatable Boats (RHIBs). The air wing consists of up to 2 x Sikorsky MH-60R/S "Seahawk" medium-lift navalized helicopters launched and retrieved from the stern-located helipad. A full service hangar is also part of the ship's makeup. Beyond this, the vessel also supports the launching and recovery of the Northrop Grumman MQ-8 "Fire Scout" unmanned helicopter system.
Armament is a mix of projectile- and missile-based weapons: a 57mm BAe Systems Mk 110 turreted deck gun is featured at the forecastle. RIM-116 Rolling Airframe Missiles (RAMs) are also installed and the Honeywell Mk 50 series of torpedoes also makes up part of the suite. Up to 4 x 30mm "Bushmaster" chain guns can be installed if needed. Extreme close-in defense is handled by 2 x 12.7mm Heavy Machine Guns (HMGs).