The Kaman SH-2 Seasprite is a ship-based helicopter, originally developed in the late 1950s as a fast utility helicopter for the United States Navy. In the 1970s, anti-submarine, anti-surface threat capabilities were added to the design, including over-the-horizon targeting, resulting in modifying most existing UH-2 models to the SH-2 Seasprite.

This aircraft extends and increases shipboard sensor and weapon capabilities against several types of enemy threats, including submarines of all types, surface ships and patrol craft that may be armed with anti-ship missiles. It served with the U.S. Navy from the 1960s until the last SH-2G helicopters were retired in 2001.

Design and development

Origins

In 1956, the US Navy launched a competition to meet its requirement for a compact, all-weather multipurpose naval helicopter.  Kaman's K-20 model was selected as the winner.  Kaman was awarded a contract for four prototype and 12 production HU2K-1 helicopters in late 1957.  Kaman's design was for a conventional helicopter powered by a single General Electric T58-8F turboshaft engine, driving a 44-foot four-bladed main rotor and a four-bladed tail rotor.

In 1960, the Royal Canadian Navy (RCN) announced that the HU2K was the frontrunner for a large anti-submarine warfare contract; the Canadian Treasury Board had approved an initial procurement of 12 units for $14.5 million.  Abruptly, Kaman raised the estimated price to $23 million, and there was concern that the helicopter's performance projections were overly-optimistic. The Naval Board decided to wait until after the USN had conducted sea trials before approving the purchase. These trials revealed the HU2K to be substantially heavier, underpowered, and incapable of meeting the RCN's requirements. Thus, in late 1961, the RCN chose the Sikorsky Sea King instead.

With no follow-on orders, Kaman ended production in the late 1960s after delivering 184 SH-2s to the US Navy; although production would be later restarted in 1971 to manufacture an improved variant of the helicopter, the SH-2F.  A significant factor in the reopening of the production line was that the Navy's Sikorsky SH-60 Sea Hawk, which was newer and more capable in anti-submarine operations, was too large to be operated from the small flight decks of older frigates.

Further development

Upon enactment of the 1962 United States Tri-Service aircraft designation system, the HU2K-1 was redesignated UH-2A and the HU2K-1U was redesignated UH-2B. In service, the UH-2 Seasprite would see several modifications and improvements, such as the addition of fixtures for mounting external stores. Beginning in 1968, the Navy's remaining UH-2s were extensively remanufactured, their single engines being replaced by a twin-engine arrangement.

The UH-2 was selected to be the airframe for the interim Light Airborne Multi-Purpose System (LAMPS) helicopter in October 1970.  LAMPS evolved in the late 1960s from an urgent requirement to develop a manned helicopter that would support a non-aviation ship and serve as its tactical Anti-Submarine Warfare arm. Known as LAMPS Mark I, the advanced sensors, processors, and display capabilities aboard the helicopter enabled ships to extend their situational awareness beyond the line-of-sight limitations that hamper shipboard radars and the short distances for acoustic detection and prosecution of underwater threats associated with hull-mounted sonars. H-2s reconfigured for the LAMPS mission were redesignated SH-2D.  On 16 March 1971, the first SH-2D LAMPS prototype first flew.

The full LAMPS I system was equipped on the SH-2F. The SH-2F was delivered to the Navy beginning in 1973. This variant had upgraded engines, longer life rotor, and higher take-off weight. In 1981, the Navy ordered 60 production SH-2Fs. Beginning in 1987, 16 SH-2Fs were upgraded with chin mounted Forward Looking Infrared Sensors (FLIR), Chaff (AIRBOC)/Flares, dual rear mounted IR scramblers, and Missile/Mine detecting equipment.

Eventually all but two H-2s then in Navy inventory were remanufactured into SH-2Fs. The final production procurement of the SH-2F was in Fiscal Year 1986. The last six orders for production SH-2Fs were switched to the SH-2G Super Seasprite variant.

Operational history

United States

The UH-2 began entering operational service in 1962.  The Navy soon found the helicopter's capabilities to be restricted by its single engine, and ordered Kaman to retrofit all of its Seasprites with a twin-engine arrangement instead; with two engines the Seasprite was capable of reaching an airspeed of 130 knots and operating at a range of up to 411 nautical miles.  The Navy would operate a total fleet of nearly 200 Seasprites for various duties, such as anti-submarine warfare (ASW), search and rescue (SAR) and transportation.  Typically, several UH-2s would be deployed upon an aircraft carrier to perform plane guard and SAR missions.

The UH-2 was introduced in time to see action in the Tonkin Gulf incident in August 1964; the Seasprite's principle contribution to what would become the Vietnam War was the retrieval of downed aircrews, both from the sea and from inside enemy territory, and was increasingly relied upon in this mission as the war intensified, such as during Operation Rolling Thunder in 1965.  In October 1966 alone, out of 269 downed pilots, helicopter-based SAR teams were able to recover 103 men.

In the 1970s, the conversion of UH-2s to the SH-2 anti-submarine configuration provided the US Navy with its first ASW helicopter capable of operating from vessels other than its aircraft carriers. The small size of the SH-2 allowed it to be operated from flight decks that were too small for most helicopters, this being a factor in the Navy's decision to acquire the improved SH-2F in the early 1980s.

SH-2Fs were utilized to enforce and support Operation Earnest Will in July 1987, Operation Praying Mantis in April 1988, and Operation Desert Storm during January 1991 in the Persian Gulf region.  The countermeasures and additional equipment on the SH-2F allowed it to conduct combat support and surface warfare missions in these hostile environments, which had an often-minimal threat from submarines. The SH-2F was retired from active service in October 1993, at roughly the same time that the Navy retired the last of its Vietnam-era Knox Class Frigates that were unable accommodate the larger SH-60 Sea Hawk.

In 1991, the US Navy began to receive deliveries of the new SH-2G Super Seasprite; a total of 18 converted SH-2Fs and 6 new-built SH-2Gs were produced.  These were assigned to Naval Reserve squadrons, the SH-2G entered service with HSL-84 in 1993. The SH-2 served in some 600 deployments and flew 1.5 million flight hours before the last of the type were finally retired in mid-2001.

New Zealand

The Royal New Zealand Navy (RNZN) replaced its Westland Wasps with four interim SH-2F Seasprites (ex-US Navy), operated and maintained by a mix of Navy and Air Force personnel known as No. 3 Squadron RNZAF Naval Support Flight, to operate with ANZAC class frigates until the fleet of five new SH-2G Super Seasprites were delivered. The Navy air element was transferred to No. 6 Squadron RNZAF at RNZAF Base Auckland in Whenuapai in October 2005. RNZN Seasprites have seen service in East Timor. Six additional SH-2Fs were purchased and are now stationed at the RNZAF Ground Training Wing (GTW) at Woodbourne near Blenheim as training helicopters. An SH-2F (ex-RNZN, NZ3442) is preserved in the Royal New Zealand Air Force Museum, donated to the museum by Kaman Aircraft Corporation after an accident while in service with the RNZN.