Sikorsky UH-34D “Seahorse” (also “Sea Bat”)

The Sikorsky H-34 (S-58) first flew on 8 March 1954 and entered service that year as an anti-submarine helicopter for the Navy (HSS-1 “Sea Bat”), later adapted as a utility transport for the Marine Corps (HUS-1 “Seahorse,” redesignated UH-34D in 1962). Marines nicknamed it the “HUS,” and its reliability led crews to request it by name in the field. It became the last piston-engined helicopter flown by the USMC, remaining in service into the early 1970s and carrying 12 to 16 troops or 8 stretcher cases per lift. The type also gained fame recovering NASA astronauts and spacecraft after Mercury program splashdowns. This airframe, Bureau Number 145694, was built in October 1958 and served the Navy and Marine Corps as both a Sea Bat and Seahorse before retiring in April 1971.

Aircraft Specifications

Physical Description

The Sikorsky H-34 (company designation S-58) was a piston-engined utility helicopter developed for the U.S. Navy as an anti-submarine platform and widely adopted by the Navy, Marine Corps, Army, and Coast Guard for transport, medevac, and search-and-rescue duties. It was the last piston-engined helicopter flown by the U.S. Marine Corps, seeing extensive Vietnam-era service before being replaced by turbine types such as the UH-1 Huey.

Crew: 2 (pilot, co-pilot); cabin capacity up to 12–16 troops or 8 stretcher cases

Length: 47 ft 2 in (fuselage); 56 ft 8.5 in with rotors turning

Wingspan: N/A (helicopter) — main rotor diameter 56 ft 0 in

Height: 14 ft 3.5 in

Weight (empty / max takeoff): 7,646 lb empty / 13,300 lb max takeoff

Powerplant: 1 × Wright R-1820-84 Cyclone 9-cylinder radial, 1,525 hp

Maximum speed: 122 mph

Range: 190 mi

Service ceiling: 12,000 ft

Weapons

None standard. A small number of USMC UH-34s were field-modified with the TK-1 armament kit (twin M60C machine guns and 2.75-inch rocket pods, nicknamed “Stingers”) for limited gunship trials in Vietnam. This airframe: none.

Key Accomplishments

H-34s served as recovery helicopters for NASA’s Mercury program splashdowns; the type was the last piston-engined helicopter flown by the U.S. Marine Corps; H-34s saw combat in Vietnam, the Dominican Republic, and the Algerian War, where French-operated examples helped pioneer modern air-assault tactics.

Note: This aircraft is painted as “Marine-1”- a replica of the aircraft used to fly President Dwight D. Eisenhower in 1957 in honor of Major General Ronald Nelson, the museum’s chairman emeritus. A dedication ceremony was held at the museum in Fall 2025.

Build Date

October 1958

Manufacturer

Sikorsky Aircraft Corporation

Dates of Service

Entered U.S. Navy/Marine Corps service 1958; retired April 1971

Country of Origin

United States

Inventory Number

Bureau # 145694

Credit

DVHAA

Display Status

Wings of Freedom Aviation Museum, Horsham, PA — outdoor static display

Status: On display