The
Sikorsky S-61R was developed as a derivative of their S-61/SH-3 Sea King model. It features a substantially revised fuselage with a rear loading ramp, a conventional, though watertight, hull instead of the S-61's boat-hull, and retractable tricycle landing gear. The fuselage layout was used by Sikorsky for the larger
CH-53 variants, and by the much later (though similarly sized)
S-92. In 1957, Sikorsky engineers were working on a new model for the
United States Navy to replace the
HUS-1s, used for anti-submarine warfare. Designated the HSS-2 (Helicopter, anti-Submarine, Sikorsky) under
the old designation system, this helicopter would enter service as the SH-3 Sea King under
the new tri-service designation system. On 9 January 1958, General
Randolph M. Pate,
Commandant of the Marine Corps, wrote to the
Chief of Naval Operations (CNO) requesting procurement of modified HSS-2s to replace the Marines'
HUS-1 helicopters. General Pate recommended that the transport version be designated the HR3S (Helicopter, Transport-3-Sikorsky). The improved
HH-3E variant would follow later, with eight built, and with all 50 CH-3Es converted to this standard. Known as the
Jolly Green Giant (because of its size and
olive green color scheme; alluding to the
Jolly Green Giant company mascot), the HH-3E featured protective armor, self-sealing tanks, a retractable inflight refueling probe, jettisonable external tanks, a high-speed hoist, and other specialized equipment. ==Operational service==