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Steps towards warship invisibility
March 03, 2008Naval warships might look like all-powerful vessels but they are also highly vulnerable to being spotted by the enemy. That fear of being detected has led the military to develop new stealth technologies that allow ships to be virtually invisible to the human eye, to dodge roaming radars, put heat-seeking missiles off the scent, disguise their own sound vibrations and even reduce the way they distort the Earth's magnetic field, as senior lecture in remote sensing and sensors technology at Britannia Royal Navy College, Chris Lavers, explains in March's Physics World.
Wars throughout the twentieth century prompted advances in stealth technologies. Some of the earliest but most significant strides towards invisibility involved covering ships with flamboyant cubist patterns - a technique known as "dazzle painting". During the Second World War, the US military even worked out a way of using lights to make the brightness of a ship match that of the background sea.
When British physicist Robert Watson Watt was charged with designing a 'death ray' to destroy entire towns and cities during the Second World War, he calculated it impossible. He did conclude however that radio waves could be used to detect ships and aircrafts too far way to be seen by the naked eye.
Radar was born. For ships to dodge radar, both a ship's geometry and a ship's coating have to be considered. Radars are particularly receptive to right angles, which is why modern battleships are often peculiarly shaped. Special paint and foam-coating have also been used to cover ships, which convert radio-waves into heat and stop radio waves being reflected, rendering the signals useless.
The "stealthiest" ship that currently exists is Sweden's Visby Corvette. Apart from being painted in grey dazzle camouflage and made of low-radar reflectivity materials, it also does not use propellers, which are the noisiest part of a ship. The vessel also has the lowest "magnetic signature" of any current warship.
But the next generation of warships could be truly invisible by exploiting "metamaterials" - artificially engineered structures first dreamt up by physicist John Pendry at Imperial College, London. Metamaterials are tailored to have specific electromagnetic properties not found in nature. In particular, they can bend light around an object, making it appear to an observer as though the waves have passed through empty space.
About the research, Chris Lavers writes, "If optical and radar metamaterials could be developed, they might provide a way to make a ship invisible to both human observers and radar systems, although the challenges of building a cloak big enough to hide an entire ship are huge."
Also in this issue:
* Full steam ahead - an interview with next CERN boss Rolf-Dieter Heuer about the challenges when the Large Hadron Collider opens later this year
* Microelectronics based on the flow of heat - the new and exciting field of 'phononics'
Institute of Physics
Radar was born. For ships to dodge radar, both a ship's geometry and a ship's coating have to be considered. Radars are particularly receptive to right angles, which is why modern battleships are often peculiarly shaped. Special paint and foam-coating have also been used to cover ships, which convert radio-waves into heat and stop radio waves being reflected, rendering the signals useless.
The "stealthiest" ship that currently exists is Sweden's Visby Corvette. Apart from being painted in grey dazzle camouflage and made of low-radar reflectivity materials, it also does not use propellers, which are the noisiest part of a ship. The vessel also has the lowest "magnetic signature" of any current warship.
But the next generation of warships could be truly invisible by exploiting "metamaterials" - artificially engineered structures first dreamt up by physicist John Pendry at Imperial College, London. Metamaterials are tailored to have specific electromagnetic properties not found in nature. In particular, they can bend light around an object, making it appear to an observer as though the waves have passed through empty space.
About the research, Chris Lavers writes, "If optical and radar metamaterials could be developed, they might provide a way to make a ship invisible to both human observers and radar systems, although the challenges of building a cloak big enough to hide an entire ship are huge."
Also in this issue:
* Full steam ahead - an interview with next CERN boss Rolf-Dieter Heuer about the challenges when the Large Hadron Collider opens later this year
* Microelectronics based on the flow of heat - the new and exciting field of 'phononics'
Institute of Physics
Warship Current Events and Warship News RSSSulfur in marine archaeological shipwrecks -- the 'hull story' gives a sour aftertaste
Advanced chemical analyses reveal that, with the help of smart scavenging bacteria, sulfur and iron compounds accumulated in the timbers of the Swedish warship Vasa during her 333 years on the seabed of the Stockholm harbour.
Preserving a 460 year old wreck
An international team of researchers has analysed the sulphur and iron composition in the wooden timbers of the Mary Rose, an English warship wrecked in 1545, which was salvaged two decades ago.
Shipworm threatens marine archeological remains in the Baltic
Shipworm has spread to the Baltic Sea. If it continues to spread, it threatens to destroy still well-preserved and irreplaceable shipwrecks and other marine archeological remains along the coast of Sweden, according to Carl Olof Cederlund, professor of marine archeology at Södertörn University College in Stockholm and the Swedish representative in the EU project that has now determined the spread of shipworm to the Baltic for the first time. "Up till now the Baltic has been regarded as a haven against shipworm. This is one of the reasons why it was possible to find the royal warship Wasa and other large wooden vessels in such excellent condition after centuries at the bottom of the s
TU Clausthal Hits the Nail on the Head: An Ancient Roman Warship on the Danube
In August 2004, an ancient Roman galley some 20 metres in length, straight and slender as an arrow, will glide over the Danube with the rhythm of 30 oarsmen during the "River Celebration" in Regensburg. Thus, the "Regina" will be the world's first seaworthy and navigable replica of a Roman warship. This project, fostered by two experts in ancient history, Prof. Dr. Christoph Sch'¤fer, University of Hamburg, und Dr. Heinrich Konen, University of Regensburg, has also been rendered possible by the expertise of Privatdozent Dr. habil. Hans Ferkel at the Institute of Materials Science and Materials Engineering at the Technical University of Clausthal.
Media invitation - Shipshape - in war and peace
There can be few other signals of a nation's intent of action that match the dispatch of the Fleet. It is therefore vital that the Royal Navy is always ready to deploy and, if necessary, to defend Britain's interests, John Coles, Chief Executive of the Warship Support Agency will tell the Royal Academy of Engineering when he gives the Lloyds's Register Lecture in London on 31 March. It is the role of the Warship Support Agency, with an annual spend of £2.2 billion and 8,000 employees, to ensure that the Royal Navy is prepared. Mr. Coles will describe the challenges and risks involved in keeping the Royal Navy at full operational capacity. The Warship Support Agency is part of the Defe
Nature press release for 21 February issue
[415859] CLONING: MEET 'CC:', THE CARBON-COPY CAT (p859) Researchers announce the birth of the first cloned cat, in a Brief Communication to Nature published online this week. The kitten, called 'Cc:' and now almost two months old, appears healthy and energetic, although she is completely unlike her tabby surrogate mother. Mark Westhusin and colleagues at Texas A&M University, College Station, created Cc: by transplanting DNA from a female three-coloured (tortoiseshell or calico) cat into an egg cell whose nucleus had been removed, and then implanting this embryo into the surrogate mother. Cc:`s coat colour suggests that she is a clone, and a genetic match between Cc: and the donor mother co
Abertay scientist is in demand for wooden ships
Dr Derek Sinclair, scientist in the University's Scottish Institute for Wood Technology (SIWT), flies to Sweden next week to speak at a conference on preserving the Vasa - a massive 16th-century wooden warship which was recovered from the seabed off Stockholm in 1961.
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