Posted on 10/16/2017 5:05:09 AM PDT by sukhoi-30mki
At 9am on the coming Monday, India’s new defence minister Nirmala Sitharaman will oversee her first warship commissioning ceremony. At the naval dockyard in Visakhapatnam, she will flag into service the INS Kiltan, India’s third Project 28 anti-submarine warfare (ASW) corvette. But there’s a significant difference between the Kiltan, and the two class types — INS Kamorta and INS Kadmatt — that came before her. A 100-tonne difference.
While the Kamorta and Kadmatt are built entirely of steel (DMR249A special grade high-tensile steel developed by SAIL in India), the Kiltan’s entire superstructure has been constructed with carbon fiber reinforced plastic — instantly shaving off 100 tons in weight from the brand new submarine hunter.
Apart from the weight saving, top sources in the Indian Navy said the advantages of the new material are four fold: (a) It provides essential corrosion resistance to the exposed superstructure, (b) improves sea-keeping ability by increasing metacentric height (a measure of the initial static stability of a floating body). And finally, (c) the use of non-metals reduces radar signature and boosts stealth specifically by suppressing extremely low frequency electromagnetic radiations.
Sources also said the Kiltan will be stealthier, more agile and a more survivable ship at sea than the two previous P28 corvettes. Weight gain from radar signature reduction work had extracted a significant price on the ship’s nimbleness and top speed during the final design stages. The decision to explore a composite superstructure was decided as an imperative for the two final ships. The Kiltan will cruise a shade faster than the two previous ships at about 24 knots.
The P28 corvette class, built by the state owned Garden Rearch Shipbuilders & Engineers (GRSE) in Kolkata, are nearly 90 per cent indigenous, says its maker. While the two ships in service are finding their feet, the class ran into rough weather with the national auditor earlier this year over delays and the fact that the ships still don’t have their full complement of armament. The Kiltan, for instance, should have been delivered by July 2014 according to the original project contract.
UPDATE: The Indian Navy just issued this official statement on the Kiltan:
Kiltan is the latest indigenous warship after Shivalik class, Kolkata class and sister Ships INS Kamorta and INS Kadmatt and sister Ships INS Kamorta and INS Kadmatt to have joined the Indian Navy’s arsenal where in a plethora of weapons and sensors have been integrated to provide a ‘Common Operational Picture (COP)’.
It 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 ship is also the first major warship to have undertaken Sea Trials of all major weapons and sensors as a pilot project prior delivery by shipyard to Indian Navy and is ready to be operationally deployed on the day of joining the Indian Navy.
The ship’s weapons and sensors suite is predominantly indigenous and showcases the nation’s growing capability in this niche area. The ship has been constructed using high grade steel (DMR 249A) produced in state-owned Steel Authority of India Limited (SAIL). With a displacement of 3500 tonnes, the sleek and magnificent ship spans 109 meters in length and 14 meters at the beam and is propelled by four diesel engines to achieve speeds in excess of 25 knots with an endurance of 3450 nautical miles.
The installed propulsion and auxiliary systems provides very low radiated underwater noise feature, required for anti-submarine warfare. Enhanced stealth features have been achieved by ‘X’ form of Hull, full beam superstructure, inclined ship sides and use of Infra Red Signature Suppression (IRSS) system designed by NSTL for cooling the Engine and Generator exhausts. About 81% of the ship is indigenous and it is well equipped to fight in Nuclear, Biological and Chemical (NBC) warfare conditions.
The ship hosts a predominantly indigenous cutting-edge weapons and sensors suite which includes heavy weight torpedoes, ASW rockets, 76 mm caliber Medium Range gun & two multi-barrel 30 mm guns as Close-in-Weapon System (CIWS) with dedicated fire control systems, missile decoy rockets (Chaff), advanced ESM (Electronic Support Measure) system, most advanced bow mounted sonar and air surveillance radar Revathi. The ship in the future would also be installed with short range SAM system and carry an integral ASW Helicopter.
As long it never enters into any type of theater of conflict, this plastic vessel seems like a great idea.
Rust, the real enemy.
In that regard, seems like a benefit.
We saw what happened when the USS Belknap collided with the USS Kennedy...her entire superstructure, made of aluminum, melted and ran in molten rivulets down into the ocean. The guy who was my mentor on my first cruise (and the Kennedy’s after the collision told me they could see the stream of molten aluminum running down the side of the hull and hissing into the ocean.
I cannot imagine if there is a fire on this ship. For sure, it is going to create a noxious, toxic smoke, worse than a usual variety.
It sounds like a good idea on paper. Carbon Fiber is lighter and stronger (in certain property performance areas) than most other metals. But I really don’t know much about the properties of Carbon Fiber when it comes to stress and flexibility.
Recall that the “new” steel used on the Titanic was the “strongest” ever. Technically, in one respect, for the time this was undisputed. But it was also less tactile and therefore more brittle. Instead of bending and bucking under stress, it split and broke. Which makes me wonder how the specific and unique properties of Carbon Fiber have been adapted or applied to improve all aspects of a submarine hull and/or superstructure.
The first thought I had? Why hasn’t the US Military implemented this? I am sure it has been considered. I assume there are some risky complications for some applications of the material having to do with its properties and performance.
Hang two 200hp Merc’s on the back and away we go.
I’m reminded of a passage from Tom Clancy’s “Red Storm Rising”, where a wing of A-10s was used to buzz a Russian warship. One of the ‘Hog pilots reflects on how the Warthog’s GAU-8 cannon, which was designed to break up Soviet Armor, would absolutely shred the lightweight superstructure of a warship. I don’t think they’re losing much by going to a composite superstructure in terms of crew protection. The only points I can see are the ones made upthread about the possible fumes created if there’s a fire onboard, and the possibility of the composite not being ductile enough. Since the Boeing 787 seems to manage to be ductile using composites, and its composites have to be a lot stiffer due to the weight restrictions imposed by flightworthiness, I would imagine that on a warship, composites can be a lot more flexible since they can use more material to maintain strength.
Wonder what it does to depth and speed of dive?
And will it be able to withstand 30-50’ seas?
AS it rests on the ocean floor they will recall that it was “such a good idea at the time and we couldn’t understand why no-one had implemented this before.”
“The first thought I had? Why hasn’t the US Military implemented this? I am sure it has been considered. I assume there are some risky complications for some applications of the material having to do with its properties and performance.”
I would imagine that we haven’t yet used this much because our procurement process is so convoluted. New designed take a long time to make it to fruition, and we haven’t built many new hull designs. I would imagine the Zumwalt incorporates at least some composite technology in its superstructure, given its tiny radar signature and the necessity of maintaining equilibrium with that tumblehome hull design.
Carbon Fiber eh? Well, it certainly will make a nice candle when it catches on fire.
Probably burn like a suttee...
Wouldn't that be decrease metacentric height ?
I noticed that too.
Metacentric is a fancy word but yeah, I’d posit that the center of gravity and tipping point would be lowered due to a lighter superstructure.
I work in the shipping classification business. I have seen lots of ships tip over.
On an academic level, it’s really fun and neat.
Good catch.
One has to wonder about the ability of surgeons to
remove CF debris from the human body...
It was a flight of F-15’s out of Keflavic shooting up the barge carrier being used by the Russians.
There was that as well, but the event I mentioned also took place. In the case of the A-10 flyover, they didn’t do anything but drop flares, but one of the pilots does think about how the DU rounds in the GAU would wreak havoc on a warship.
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