Impetus From the immediate post-Second World War era, the
Royal Navy sought a general-purpose weapon suitable for arming smaller ships. Experience with German
glide bombs during the war showed the need for a medium-range
surface-to-air missile capable of destroying bombers before they could reach a range for launching glide bombs. As such a system would occupy space normally used for a
dual-purpose gun, it was also intended to have a secondary anti-ship capability, although this requirement was later reduced. Extensive research and trials in the 1950s produced the
Seaslug system. While effective against first-generation
strike aircraft, its performance against faster aircraft and
anti-ship missiles was limited, and its size made it unsuitable for
frigate-sized ships. A high-performance gun concept, the DACR (direct-action, close-range), was considered, but calculations showed it would be ineffective against future manoeuvring anti-ship missiles. Two systems were initially considered for the role.
Bristol's RP.25 was a
ramjet powered design with a long
ogive wing that was boosted to speed by two detachable booster rockets under the missile. The layout was not that different from Bristol's recently introduced
Bloodhound missile. The second proposal was a two-stage solid-fuel rocket known as SIG-15 from BAC, developed partially from BAC's work on the PT.428 which would later emerge as
Rapier. The Admiralty considered the range of the BAC entry, about , to be too short to be useful. The Bristol concept offered a much more useful maximum around . However, they also felt the BAC team, known as Project 502, was better able to manage the project. The Admiralty also demanded that the design be able to be moved about the ship in a fashion similar to gun ammunition, which made the winged RP.25 unsuitable. The result was a redesign effort with BAC designing the airframe and Bristol providing the engine.
CF.299 The new design was returned in 1962, and was so promising that the
Ministry of Aviation assigned it the name CF.299 and detailed design began. By this time, many European navies had chosen the much shorter-range US
RIM-24 Tartar surface-to-air missiles for their newer ship designs, but the
Dutch Navy was interested in the British missile for a new class of advanced anti-air ships they were designing. The design mounted an advanced radar system, and an agreement was arranged where the Dutch would use the British missile and the RN ships would use the Dutch radar under the name Type 988 "Broomstick". This was a 3D radar with multiple antennas that provided both fast continual scanning as well as multiple independent targeting radars. Both the radar and missiles would be controlled by a new combat direction system being developed by both navies. The Navy dropped its interest in Broomstick and continued development using simpler radars like the
Type 965 radar that was already in service. This had the disadvantage of not being able to pick out targets against a background landform or high waves, significantly limiting its capabilities against low-flying strike aircraft. but this fell through in 1983, with Chinese minister
Chen Muhua explaining that China was "not satisfied with the price, technology or production".
Proposed versions During the late 1970s, British Aerospace proposed a Sea Dart II, which replaced the original's transistor-based electronics with
integrated circuits that so reduced the size of the equipment that it allowed for a useful increase in fuel storage and range. British Aerospace also outlined a new version of the Chow booster that included
thrust vector control that would allow it to be stored vertically on new platforms or make radical manoeuvres when launching from the existing launch rail systems. Development was cancelled in the 1980 Defence Review by the Minister of Defence,
John Nott. Another short-lived project was Sea Daws 100, which used a single-rail launcher for a future Type 82 replacement.
Hawker Siddeley Dynamics, which had taken over Bristol, proposed using the Sea Dart missile as a replacement for both the
British Army's
Thunderbird and the RAF's
Bloodhound. This Land Dart was launched from a four-round box that would be highly mobile. Hawker Siddeley Dynamics suggested that if the missile was used by all three British services, it would result in further sales as a
NATO-standard SAM. The introduction of the VR.725 Thunderbird II led the Army to drop any interest in Land Dart, and the NATO contract eventually went to the
MIM-23 Hawk. Hawker Siddeley tried again in the 1970s when the Air Staff released GAST.1210, calling for a long-range missile to replace Bloodhound. They proposed a further updated Land Dart combined with a dramatically improved radar system, the Plessey GF75 Panther, a land-based version of the naval AWS-5. This concept ultimately went nowhere and the Bloodhound was removed from service in 1991 with no replacement. In the early 1980s,
British Aerospace (BAe), who had taken over Hawker, re-launched the GAST.1210 concept under the new name Guardian. This proposed a lightweight two-round launcher and mobile version of Panther to be used as both a SAM and an anti-missile for short-range
ballistic missiles like
SCUD. Despite interest from the Middle East, no sales followed. The same launcher was also offered as Lightweight Sea Dart, which used its disposable shipping container as the launch tube, which was fit into a four-place trainable launcher that could also mount
Sea Eagle. Most of the weight savings was in the launcher itself, allowing it to be fit to smaller ships.
Updates Experience in the
Falklands War demonstrated that the mix of systems used to support Sea Dart put it at a significant disadvantage despite the missile itself being highly potent. This led to a series of updates to both the missile and the radars equipping the
Sheffield-class destroyers. The first upgrade was to replace the older Type 965 radar with the much better Type 1022. The Navy had originally planned on replacing the 965 with a new radar, then known as STIR, when it became available. As it became clear that STIR would not be available for some time,
Marconi offered an interim model, the 1022. This had a new antenna design that greatly reduced the beamwidth from around 12 degrees to 2.3, and used a shaped broadcast pattern that greatly reduced the amount of signal that was aimed at waves and thereby reduced clutter. The 1022 arrived in time to equip the "Batch II" Sheffields, which began in 1978 with HMS
Exeter. Initially they had planned to re-equip the earlier ships as well, but as the new ships started arriving all desire to spend the money on the upgrades disappeared. As many of the problems with the Sea Dart could be traced to the failure of the 965 to provide any early warning against low-level engagements, the ability to offer dramatically improved performance with a relatively simple update that had been planned all along was suddenly considered very important. ==Design==