The Swedish diesel-electric submarine HSMS Gotland quietly approached without being detected, then they launched mock torpedoes to destroy the aircraft carrier USS Ronald Reagan during a US exercise in 2005.
The powerful escort fleet of the aircraft carrier USS Ronald Reagan failed to detect the small Swedish diesel-electric submarine during the simulated attack. This stunned the US and NATO.
In 2005, the newly built US$6.2 billion aircraft carrier USS Ronald Reagan and its escorts took part in a simulated defense exercise, rivaling the Gotland-class light submarine HSMS Gotland. leased from Sweden to the United States for one year.
This light submarine quietly bypassed the many layers of dense protection of the American escort and repeatedly fired mock torpedoes at the USS Ronald Reagan aircraft carrier. After “sinking” the enemy ship, the submarine HSMS Gotland left when the American fleet had not yet realized its presence.
The US Navy held many such exercises with the Gotland submarine in its first year, but each time its destroyers and nuclear attack submarines succumbed to the small submarine with a displacement of only 1,380 tons of Sweden.
Impressed with the ability to bypass the anti-submarine defense system equipped with many modern sensors from the escort squadron USS Ronald Reagan of the submarine HSMS Gotland, the US Navy decided to lease this ship for another year to find out. its tactical technical features.
HSMS Gotland of the Gotland class is an electric – diesel submarine with a relatively cheap price, only about 100 million USD. This figure is only 1/3 of the purchase of Russian Kilo submarines.
HMS Gotland submarine is 60.7 meters long with a displacement of 1380 tons. After upgrading, the submarine HMS Gotland has a length of 62.7m. The ship has a speed of 11 knots when floating and 20 knots when submerged. Maximum crew of 32 people. Weapons equipped on the ship include four 533 mm torpedo tubes; two 400 mm torpedo tubes; 48 external weapon mounts.
The submarine is equipped with the Stirling Mk3 AIP system; The combat system, the ES-3701 electronic warfare (EW) system as well as the management, sensing and communication systems are constantly being updated.
The fact that the entire aircraft carrier fleet was defeated by a small submarine surprised the US and looked back on the role of this non-nuclear submarine. The US Navy has phased out all diesel submarines since 1990 to focus on developing larger, more powerful nuclear attack submarines.
In the past, diesel submarines were limited by their noisy engines, being able to stay underwater for only a few days before having to surface to get air for their engines, making them vulnerable to enemy aircraft detection and attack. In contrast, nuclear-powered submarines do not require large air supplies, can operate quietly underwater for months, and have higher speeds.
However, the Gotland-class submarine launched in 1996 was the first submarine to use an air-independent propulsion (AIP) system to reduce dependence on external air sources. They can stay submerged for up to two weeks while maintaining an average speed of 9.6 km / h, or when necessary can accelerate up to 37 km / h.
Diesel engines are used when the vessel is afloat or using a vent pipe. Gotland-class submarines run much quieter than nuclear submarines, which use a very noisy reactor cooling system.
Gotland-class submarines have many other features that make them very difficult to detect. It is equipped with 27 electromagnets, capable of hiding the magnetic signal from the sensor that detects the anomalous magnetic field. The hull is covered with sonar material, while the conning tower is made of radar-absorbing material.
The machinery on the ship is covered with rubber cushions to reduce noise, limiting the possibility of being detected on the enemy’s passive sonar. The HSMS Gotland is highly maneuverable thanks to six control surfaces on the X-shaped rudder and conning tower, allowing it to operate near the seabed and perform sharp turns.
After two years of exercises, the US Navy realized HSMS Gotland was the biggest challenge for its anti-submarine force and the undersea sensor system being equipped could not cope with AIP submarines.
Gotland-class submarines are just one of many types of AIP submarines in the world. Russia and China, Spain, France, Japan and Germany all design and own diesel-electric submarines with stealth capabilities. AIP submarines evolved into larger, more powerful and expensive weapons, typically the German Dolphin class and the French Scorpene class.
Diesel submarines are most effective when attacking enemy fleets when their location is known through intelligence. However, they have the disadvantage that their slow underwater speed makes them unsuitable for tracking moving targets over large seas.
The advent of inexpensive, stealthy, and long-range diesel submarines puts aircraft carriers and other expensive warships at greater risk when operating near enemy shores.
According to military experts, AIP submarines will be an effective means to protect the coastal coast and raid the enemy’s large fleets, which poses a new challenge in sea warfare. Even the US is having a headache to find a way to cope.