The US believed it had an invincible aircraft carrier. Until Sweden “knocked him down” again and again with a tiny submarine

Exactly 20 years ago there was a fascinating scene which showed that brute force or dimensions monstrous They are not as fundamental as was believed when it comes to naval warfare. Shortly before that true story, the United States had announced to the four winds its most modern, heaviest and most grandiose nuclear aircraft carrier in history.

So they took the most logical step: put it to the test.

The exercise that turned out regular. In 2005, during maneuvers off the coast of California, the United States Navy allowed something unusual: Repeatedly engage a small, relatively inexpensive foreign conventional submarine to improve its anti-submarine doctrine. The chosen one was HMS Gotlanda Swedish diesel-electric submarine of just 1,600 tons. The objective was to train the aircraft carrier battle group USS Ronald Reaganone of the most powerful ships in the world, equipped with escorts, anti-submarine helicopters and advanced sensors.

What followed it was unexpected: Time and time again, over two years of simulations, the Gotland managed to infiltrate the formation, position itself to fire, and “sink” the carrier without being detected. The result caused concern in Washingtoninterest in Moscow and Beijing, and a profound reassessment of the role of modern diesel submarines in contemporary naval warfare.

The Gotland and the silent advantage. Gotland’s success was based on its system Air Independent Propulsion (AIP), specifically a Stirling engine capable of generating energy without needing to take air from outside. This allowed the ship to remain submerged for up to two weeks, maintaining a constant speed and extremely quiet, something that previous diesel versions they could not achieve.

While nuclear submarines require cooling systems that generate detectable vibrations and noise, the Gotland could move almost without leaving an acoustic trace. Its hull was covered with materials that decreased sonar reflection, its tower included radar-absorbing materials, and the internal machinery was mounted on rubber shock absorbers to silence vibrations. Furthermore, it had with 27 electromagnets capable of reducing their magnetic signature before specialized sensors.

Mobility and stealth. The Gotland maneuverability It was also decisive. Its design with X-shaped rudders and automated control systems allowed sudden changes in course and depth with great precision, making it suitable for operating in shallow coastal waters, where nuclear submarines are most vulnerable.

In the context of the maneuvers against USS Ronald Reaganthe Gotland demonstrated that it could approach at great depth, obtain a firing position, and withdraw before American sensors will even detect alterations in the environment. Although in a real combat the aircraft carrier could survive several impacts, the essential fact is that it would have been knocked out of combat, which would change the strategic outcome of any naval operation.

Economic and doctrinal threat. The Gotland cost about 100 million of dollars, which is approximately equivalent to the cost of two embarked F/A-18 aircraft. The USS Ronald Reagan, on the other hand, cost more than 6 billionwithout counting its escort or its air wing. In terms of cost-effectiveness, a relatively affordable submarine demonstrated that could neutralize an asset which represents the core of US naval projection. This revelation resonated especially in China and Russiawhich have since accelerated the development of AIP submarines.

Today, China operates multiple submarine variants equipped with Stirling and Russia works on updated versions from the Lada projectwhile countries such as Japan, Germany, France, Israel, India and South Korea also develop or acquire submarines of this type. The challenge is not only technical, but also strategic: a small number of submarines of this type can make it difficult to use aircraft carriers near hostile coastlines, altering the way powers deploy their force.

The “no” to diesel in the US. Despite the impact of the exercise, the US Navy decided not to repeat operate diesel submarines. Their reasoning is based on logistics and strategic reach: the United States deploys submarines thousands of miles from their bases, and needs units that can operate for monthspursue targets at long distances and sustain high speeds without the need to recharge batteries.

Diesel-AIP submarines are ideal for defending territorial waters or coastal areas, but less suitable for prolonged ocean operations. For this reason, the US Navy has preferred to invest in nuclear submarines and, more recently, in unmanned underwater systems that could complement or replace escort and patrol missions.

What the Gotland revealed. The history of HMS Gotland proves that naval supremacy is not guaranteed for size or cost of combat platforms, but for technological adaptation and understanding the strategic environment. Aircraft carriers remain formidable tools for projecting power, but their vulnerability to silent AIP submarines forces rethink doctrinesinvest in advanced detection and reconsider the type of forces used in environments close to enemy coasts.

The key lesson was not the symbolic sinking of an aircraft carrier, but the realization that 21st century naval warfare can turn hierarchies upside down that seemed immovable. Those days showed that, in the ocean, silence is worth more than steel, and a small submarine can change the balance of an entire fleet.

Image | WikimediaUS Navy

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