Stealth ship

The U.S. Navy's Sea Shadow (IX-529)

File:Juan ricardo oyola vera.jpg

Juan Ricardo Oyola Vera in Cartagena

A stealth ship is a ship which employs stealth technology construction techniques in an effort to ensure that it is harder to detect by one or more of radar, visual, sonar, and infrared methods. These techniques borrow from stealth aircraft technology, although some aspects such as wake and acoustic signature reduction are unique to stealth ships' design.

Reduction of radar cross section (RCS), visibility and noise is not unique to stealth ships; visual masking has been employed for over two centuries and RCS reduction traces back to American and Soviet ships of the Cold War. One common feature is the inward-sloping tumblehome hull design that significantly reduces the RCS.

Examples

Several surface vessels employ stealth technology, amongst them the Swedish Visby class corvette, the Dutch Zeven Provinciën class frigate, the Norwegian Skjold class patrol boat, the French La Fayette class frigate, the Chinese Houbei class missile boat and Type 054 frigate, the German MEKO ships Braunschweig class corvettes and Sachsen class frigates, the Indian Shivalik class frigate, the Singaporean Formidable class frigate the British Type 45 destroyer, the U.S. Navy's Zumwalt-class destroyer and Finnish Hamina class missile boats.

HMS Helsingborg, one of the Swedish Navy's Visby class corvettes.

French frigate Surcouf of the La Fayette class

File:Hr. Ms. Evertsen (F805).jpg Dutch destroyer HNLMS Evertsen (F805) (Zeven Provinciën class)

The Visby was the first stealth ship to enter service, and is designed to elude visual detection, radar detection, acoustic detection, and infrared detection. Its surface is constructed from a carbon fibre reinforced plastic. Avoidance of right angles in the design results in a smaller radar signature, reducing the ship's detection range.

Britain's Type 45 Anti Air Warfare Destroyer has similarities to the Visby, but is much more conventional, employing traditional steel instead of carbon fibre. Like the Visby, its design reduces the use of right angles.

The currently developed U.S. Zumwalt class destroyer — or DD(X) — is the US version of a stealth ship. The Sea Shadow, which utilizes both tumblehome and SWATH features, was an early U.S. exploration of stealth ship technology. The Arleigh Burke class also employs stealth technology without being a full stealth ship, similar to the German designs.

German Braunschweig class corvette (F 261)

Artist's conception of the USS Zumwalt, the lead ship of the planned Zumwalt class of destroyer for the U.S. Navy

Type 45 Royal Navy destroyer

Shaping

In designing a ship with reduced radar signature, the main concerns are radar beams originating near or slightly above the horizon (as seen from the ship) coming from distant patrol aircraft, other ships or sea-skimming anti-ship missiles with active radar seekers. Therefore, the shape of the ship avoids vertical surfaces, which would perfectly reflect any such beams directly back to the emitter. Retro-reflective right angles are eliminated to avoid causing the cat's eye effect. A stealthy ship shape can be achieved by constructing the hull and superstructure with a series of slightly protruding and retruding surfaces. This design was developed by several German shipyards, and is thus extensively applied on ships of the German Navy.

See also

Sloped surface features visible in this frontal view of the Hamburg, a Sachsen class frigate of the German Navy

• F125 class frigate
• Formidable class frigate
• Zeven Provinciën class destroyer
• Kolkata class destroyer
• Sachsen class frigate (F124) frigate
• Brandenburg class frigate (F123) frigate
• Braunschweig class corvette
• Type 45 destroyer
• Type 054 frigate
• La Fayette class frigate
• Shivalik class frigate
• Sa'ar V class missile boat
• Visby class corvette
• Skjold class patrol boat
• Sea Shadow experimental ship
• Valour class frigate
• ARC TF Juan Ricardo Oyola Vera Colombian patrol ship
• Hamina class missile boat
• Radar cross section
• Infrared signature

External links

• Visby
• DDG 1000 information; formerly DD(X)
• Shivalik class frigate
• Stealth ships steam ahead article by Chris Summers on BBC news, 10 June, 2004
• Ghost ships: the latest in stealth ship technology article on the website www.military.com