What makes warships like the INS Kiltan stealthy when the superstructure is not symmetric?
The main detectors that find out whether a navy vessel of an enemy country is in the oceanic water are the SONAR, the radar and the Infrared. Stealth ships are designed in such a way that they are invisible to the radar and other detecting technologies. Also, since they are invisible but the opposite navy vessels are not, it gives a very big boost and advantage to the stealth ships to successfully launch an attack.
The major feature that is taken into account while constructing a stealth ship is about right angles. Conventional ships are designed in such a way that they deflect and reflect the radar and infrared rays that hit. This reflecting surface is known as the Radar Cross Section (RCS). By not constructing the ships with any right angles, such deflection and emerging RCS are avoided, making the ship a stealth ship.
The technology for the stealth ship was first developed and used by the German navy. Over the years almost every country has adopted the technology quite successfully. At present, the Swedish navy is known to be the best designer of such navy vessels. The Swedish navy’s Visby Corvette ship is quite unique in its designing and is known as the market leader along with a few other stealth ships under the category of ‘Visby-Class.’
According to the Swedish navy, the first of the Visby Class corvettes, which is currently sitting in the naval dockyard in Karlskrona, is a completely new type of warship: a frigate that is lighter and faster than a conventional ship and almost invisible to enemy detection. It is the largest vessel ever built from carbon fibre – a super-hard, lightweight plastic – which also marks a breakthrough in shipbuilding materials.
Some of the other navy vessels that operate as stealth ships are the British Type 45, Germany’s Braunschweig Corvettes, India’s Shivalik range of ships and China’s Houbei missile boat. The stealth technology used in these ships needs to be constantly updated for navies of countries around the world keep on updating their combating technology continuously.
Kiltan is the latest indigenous warship after Shivalik class. According to a Navy statement released earlier, this is the third of the four Kamorta-class corvettes being built under Project 28. INS Kiltan is India’s first major warship to have a superstructure of carbon fibre composite material resulting in improved stealth features, lower top weight and maintenance costs, the Indian Navy statement added.  INS Kiltan is 100 tonnes lighter than the previous corvettes.
Regarded as a very prestigious acquisition, INS Kiltan is one of the most potent warships to have been constructed in India. The ship has enhanced stealth features resulting in a reduced Radar Cross Section (RCS) achieved by X-form of hull and superstructure along with optimally sloped surfaces. The very low under water acoustic signature makes it a ‘silent killer on the prowl’. This has been achieved by using advanced techniques for propeller design and mountings of main machinery. The ship’s advanced stealth features make her less susceptible to detection by the enemy and help in effective employment of soft kill measure like the Chaff.
Partnering nation’s ‘Make in India’ drive, Steel Authority of India Ltd. (SAIL) has supplied defence grade DMR 249A steel plates for the indigenously built Anti-Submarine Warfare (ASW) stealth corvette INS – Kiltan. DMR 249A is a low carbon micro-alloyed grade of steel with stringent toughness requirement at sub-zero temperature.
Specifics of the Question
Symmetry of Top Superstructure is not as important as the metallurgy, sloping and detection avoidance features above water as well as underwater.
The Swedes decided to switch from steel to plastic – two layers of carbon fibre filled with a PVC-like foam – in the search for a radar resistant material. By using a composite material, they found one that could dramatically reduce a ship’s signature, making it not only less detectable by radar, but also less prone to enemy mines and other forms of electronic detection such as infrared. And if it is detected, the Visby should be quick enough to escape as it is only half as light as a conventional corvette.
Moreover, in searching for a radar-resistant material, the Swedes seem to have stumbled across a technology that could offer improved strength and rigidity, lower weight and better shock and flame resistance than steel. Kockums, the ship’s builder, says ships made from carbon fibre enjoy lower running and maintenance costs and lower fuel consumption.
“The use of composite materials is very exciting,” says Stephen Saunders, editor of Jane’s Fighting Ships. “There is no reason why ships should not be made of carbon fibre as long as they are up to the job. The fact that the Americans are using it in the superstructure in their next destroyers certainly points in that direction.”
Due Credits Hitesh Lav,Former Worked With Indian Navy in Joint Ops at Indian Army