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"In 1966, the Portsmouth ship-builders, Vosper Ltd., merged with the Southampton-based John I. Thornycroft to form Vosper Thornycroft, a publicly quoted engineering group, with an annual turnover of £250 million and currently employing 4000 staff. The company has a reputation for designing and building fast, innovative naval vessels and has one of the most advanced naval shipbuilding yards in Europe, with the capability of building in steel, aluminium or fibre-reinforced plastic. VT's reputation for ground-breaking technology has most recently seen the company develop the Sea Wraith stealth warship concept. Sea Wraith incorporates several advanced features which are set to become essential elements in the warships of the future where the major emphasis will be on stealth. A low profile and uncluttered exterior are designed to give a much reduced radar cross section, thus impeding radar detection and confusing an attacking missile control system. The ship can also produce a cloud of water fog to provide cover for infra-red hotspots. With a length of 138 metres, Sea Wraith's gas turbine and electric engines give her a top speed in excess of 28 knots. Armed with 1 x 127mm and 2 x 35mm gun mountings, surface-to-surface and surface-to-air missile systems, an artillery rocket weapon system and helicopter-launched torpedoes and depth charges, Sea Wraith has a variety of sensors including an unmanned aerial vehicle (UAV) system with 4 aircraft."
"Sea Wraith II the result of further Research and Development work following the unveiling of the company’s first radical stealth warship design almost a year ago.
Sea Wraith II is bigger and more capable but retains many of the innovative features from the original design which captured the imagination of navies world-wide when it was launched in Paris in October 1996.
Since then, VT has funded a series of trials and experiments to confirm the key features of Sea Wraith, while serving naval personnel have contributed their views based on the lessons learned from recent conflicts.
Sea Wraith II is a 135 metre frigate design that incorporates a flight deck, hangar and more powerful armament. The aim has been to incorporate design changes necessary to enhance its naval capability but at the same time maintain the low signatures of the ship.
The essential elements which made the original Sea Wraith such a revolutionary addition to warship technology remain in the latest design, notably:
Use of a water mist to mask the infra-red (IR) ship signature with a view to countering IR homing missiles.
A water fog diesel exhaust system which cools emissions to the ambient temperature of the ship structure and thus avoiding IR detection of hot spots.
Two masts asymmetrically positioned to maximise radar glint as a counter to radar homing missiles.
Employing a retractable mast which can vary the ship's radar signature to impede validation of the ship's radar profile by a potentially hostile maritime surveillance aircraft. This periscope mast can carry a surveillance optronic sensor which operate above the water mist.
Communications antennae enclosed within the vessel's stealth profile.
All these features have now been further proven by trials or digital simulation. Trials and testing have also included a series of wind tunnel tests to evaluate wind flow over the ship for water mist distribution and helicopter operations.
Brian Spilman. head of VT's Future Projects Group, explained: "Over the past 12 months Sea Wraith has evolved to balance all features of its design. Our original ideas have been borne out by our Research and Development programme. For example, we have confirmed that our revolutionary water mist does not degrade our own ship's radar cross section or our own ship's radar sensors."
Sea Wraith II can accommodate an EH101 or equivalent helicopter and carries more powerful armament. The ship has double the surface-to-air missile capability of its smaller sister, Sea Wraith I, with 32 missiles in two dispersed sites. The addition of a 127mm gun mounting on the foredeck provides conventional NGS in addition to the 160mm artillery rocket shore bombardment and Millennium air defence weapons.
Although retaining the beam of the original vessel, Sea Wraith II has a superstructure set in from the sides. This allows access to the weather deck to allow casualty evacuation, improve fire fighting performance in the event of damage and reduce the disturbance to helicopter landing wind flow from large flat structures.
Another notable addition is the inclusion of twin funnels. With the success of VT's diesel electric propulsion cooling experiments, the proven temperature/cleanliness of the exhaust gas and uptake ducting allows much greater flexibility in positioning exhaust outlets. The shaping of the funnels has been arranged to avoid detracting from glint generation.
Sea Wraith II will continue to undergo further trials and evaluation of its stealth capability and associated features. Mr Spilman added: "\/T has taken stealth warship design one step further than the original Sea Wraith concept. Our Research and Development work now allows us to offer unique improvements to Surface Warship Stealth Design."
"Sea Wraith II the result of further Research and Development work following the unveiling of the company’s first radical stealth warship design almost a year ago.
Sea Wraith II is bigger and more capable but retains many of the innovative features from the original design which captured the imagination of navies world-wide when it was launched in Paris in October 1996.
Since then, VT has funded a series of trials and experiments to confirm the key features of Sea Wraith, while serving naval personnel have contributed their views based on the lessons learned from recent conflicts.
Sea Wraith II is a 135 metre frigate design that incorporates a flight deck, hangar and more powerful armament. The aim has been to incorporate design changes necessary to enhance its naval capability but at the same time maintain the low signatures of the ship.
The essential elements which made the original Sea Wraith such a revolutionary addition to warship technology remain in the latest design, notably:
Use of a water mist to mask the infra-red (IR) ship signature with a view to countering IR homing missiles.
A water fog diesel exhaust system which cools emissions to the ambient temperature of the ship structure and thus avoiding IR detection of hot spots.
Two masts asymmetrically positioned to maximise radar glint as a counter to radar homing missiles.
Employing a retractable mast which can vary the ship's radar signature to impede validation of the ship's radar profile by a potentially hostile maritime surveillance aircraft. This periscope mast can carry a surveillance optronic sensor which operate above the water mist.
Communications antennae enclosed within the vessel's stealth profile.
All these features have now been further proven by trials or digital simulation. Trials and testing have also included a series of wind tunnel tests to evaluate wind flow over the ship for water mist distribution and helicopter operations.
Brian Spilman. head of VT's Future Projects Group, explained: "Over the past 12 months Sea Wraith has evolved to balance all features of its design. Our original ideas have been borne out by our Research and Development programme. For example, we have confirmed that our revolutionary water mist does not degrade our own ship's radar cross section or our own ship's radar sensors."
Sea Wraith II can accommodate an EH101 or equivalent helicopter and carries more powerful armament. The ship has double the surface-to-air missile capability of its smaller sister, Sea Wraith I, with 32 missiles in two dispersed sites. The addition of a 127mm gun mounting on the foredeck provides conventional NGS in addition to the 160mm artillery rocket shore bombardment and Millennium air defence weapons.
Although retaining the beam of the original vessel, Sea Wraith II has a superstructure set in from the sides. This allows access to the weather deck to allow casualty evacuation, improve fire fighting performance in the event of damage and reduce the disturbance to helicopter landing wind flow from large flat structures.
Another notable addition is the inclusion of twin funnels. With the success of VT's diesel electric propulsion cooling experiments, the proven temperature/cleanliness of the exhaust gas and uptake ducting allows much greater flexibility in positioning exhaust outlets. The shaping of the funnels has been arranged to avoid detracting from glint generation.
Sea Wraith II will continue to undergo further trials and evaluation of its stealth capability and associated features. Mr Spilman added: "\/T has taken stealth warship design one step further than the original Sea Wraith concept. Our Research and Development work now allows us to offer unique improvements to Surface Warship Stealth Design."
