Medium endurance cutter

[4] After World War II, the United States Coast Guard used the US Navy hull classification system.

The large, sea-going cutters were classified primarily as Coast Guard gunboats (WPG), destroyer escorts (WDE), and seaplane tenders (WAVP).

[5] The Coast Guard harvested weapons systems components from decommissioned Oliver Hazard Perry-class frigates to save money.

Equipment such as the Mark 75, 76 mm/62 caliber gun mounts, gun control panels, barrels, launchers, junction boxes, and other components from decommissioned Oliver Hazard Perry-class frigates were returned to service aboard Famous-class cutters in order to extend their service lives into the 2030s.

[6] The service life extension (SLEP) program started in July 2021 with prototype work for electrical and structural systems on the Seneca and Harriet Lane.

[5] The 210s (210-foot cutters) received upgrades and modifications (in a program named "Midlife Maintenance Availability" or MMA) during the 1986 through 1990 time period.

Other modifications included enlarging the superstructure area, replacing the main armament, and increasing the fire-fighting capability of the cutters.

USCGC Harriet Lane moored at Guantanamo Bay Naval Base .
The cutter USCGC Seneca in the Casco Bay in Falmouth, Maine. Chebeague and Little Chebeague Island are behind her.
USCGC Diligence (WMEC-616) in 1965. Note the lack of exhaust stacks and the exhaust ports at the waterline on the transom on the original design. Reliance class cutters would have stacks added during future overhauls.