In the latter stages of the Cold War period (1947-1991), the United States Coast Guard (USCG) made a decided move to update nearly all of its at-sea, over-water assets with procurement set to cover a wide range of maritime-minded aircraft, ships and the like. The program was named the "Integrated Deepwater System Program" and was to involve (but not limited to) acquisition of the Northrop Grumman RQ-4A "Global Hawk" UAV, CASA CN-235 and Lockheed C-130 high-winged transports, and an all-new family of cutter vessels such as the National Security Cutter (NSC), the Offshore Patrol Cutter (OPC) and the Fast Response Cutter (FRC). However, the decades-long initiative eventually lost support, in turn, its funding in 2012.
Some assets were obtained such as the aforementioned NSC ships - known as the "Legend-class". Eleven are planned for the USCG and six have seen active service, one undergoing sea trials, two under construction and two more on order. The class represents the largest and most advanced fighting ships of the USCG and these have been used to succeed the outgoing Hamilton-class ships of 1960s origin. The newer ship class are constructed by Ingalls Shipbuilding.
Such warships are used to enforce United States maritime territorial areas and, as such, USCG elements typically are used for trafficking interception (migrant, drugs, etc...), general law enforcement, deterrence, humanitarian assistance, disaster relief, Search and Rescue (SAR), counter-terrorism, fisheries enforcement, environmental support and will also operate under the direction of the United States Navy when needed.
Legend-class ships certainly look the part of military patrol vessel. These ships are sleek with "stealthy" slab-sides and overall low profiles. The forecastle is home to a turreted main gun in the "A" position while the bridge sits high above this emplacement with commanding views of the ocean ahead. The hull superstructure integrates the bridge section, main mast, smoke funnel and aft- hull section / hanger.
Over the stern is seated a single-helicopter helipad supporting the USCG's Eurocopter (now Airbus Helicopters) MH-65C "Dolphin" MCH navalized helicopter system. Up to two medium-lift helicopters can be carried with use of the hangar for storage however. Additionally there is support for up to 2 x (vertically-launched) Unmanned Aerial Systems (UASs). The onboard hangar provides full-service facilities for the rotary-wing aircraft. Up to three Rigid-Hull Inflatable Boats (RHIBs) are stowed and launched from the stern area for fast interception and these encompass two distinct designs, the 35-foot CB-LRI-II and the 26-foot CB-OTH-IV.
Onboard is a crew of 122 and the vessel can support as many as 148. Food and fuel allow the warship to be on station for up to 60 days. The Legend-class is equipped with all-modern sensors and processing systems including the EADS 3D TRS-16 series AN/SPS-75 air-search radar, the AN/SPS-73 surface-search radar and the SPQ-9B fire control radar system. The AN/SLQ-32(V)2 serves in the Electronic Warfare (EW) role and 2 x SRBOC and 2 x NULKA launchers are used in the chaff decoy role.
Armament includes a single 57mm Mk 110 turreted deck gun (the same as featured in the USN's Littoral Combat Ships) over the forecastle and 1 x 20mm Phalanx Block 1B Baseline 2 Close-In Weapon System (CIWS). Up to 4 x 12.7mm M2 Browning heavy machine guns are also installed as are 2 x 7.62mm M240 medium machine guns for extreme close-in work. All this is in addition to any personal weapons also carried by the crew.
The 4,500 tons (long) ships measure 418 feet long and have a beam of 54 feet and draughts down to 22.5 feet. A COmbined Diesel-and-Gas (CODAG) arrangement is used for propulsion involving 2 x MTU 20V 1163 series marine diesels of 9,900 horsepower mated to 1 x LM2500 gas turbine of 30,000 horsepower output. All told, the vessels can achieve ocean-going speeds of 28 knots and improved seakeeping helps them maintain balance in rough seas when far from shore and better endurance means more time on station. Onboard systems allow for full interoperability with existing United States Navy systems and sub-systems.
The ships-of-the-class currently (2018) include USCGC Bertholf (WMSL-750), UCGC Warsche (WMSL-751), USCGC Stratton (WMSL-752), USCGC Hamilton (WMSL-753), USCGC James (WMSL-754), USCGC Munro (WMSL-755), USCGC Kimball (WMSL-756), USCGC Midgett (WMSL-757), USCGC Stone (WMSL-758) and two unnamed vessels (WMSL-759 and WMSL-760). Bertholf, Waesche, Stratton, Hamilton, James and Munro are all in active service. Kimball is undergoing its requisite sea trials. Midgett and Stone are under construction as of 2018.
The family began commissioning in August of 2008 (with Bertholf) with the latest addition being Munro, adopted in April of 2017.