When a 100 million dollar ship sank a 13 billion dollar one

Sometimes an outsider manages to record an unexpected success, which should make you think. In 2005, during a U.S. Navy exercise, the Swedish diesel-electric submarine HSMS Gotland penetrated the defenses of the USS Ronald Reagan carrier group, striking with simulated torpedoes multiple times over the course of two years. This alarming feat highlighted the vulnerability of aircraft carriers to cheaper, stealthier submarines.

-The Gotland, costing only $100 million and equipped with Stirling engines, proved almost silent to enemy sonars. The incident highlights the continued relevance of anti-submarine strategies, especially as tensions with China rise.

Aircraft carriers are the most expensive warships around. The most advanced aircraft carrier in the world, the USS Gerald R. Ford, has a price tag of $13 billion. Although it is the extreme end of the spectrum, this price is not too far from the average cost of an aircraft carrier, which ranges from $5 billion to $9 billion.

The high cost highlights the strategic and operational importance of aircraft carriers. Aircraft carriers can project power and foreign policy like few other weapons systems in the world. In fact, the aircraft carrier is used as a tool to project a country’s power abroad.

Given this particular importance, an aircraft carrier is normally accompanied by a more or less numerous attack group that accompanies ships that have the task of supplying, escorting and protecting the main vessel. These are normally destroyers and frigates, many of which are specialized in hunting submarines, which create a multi-layered protection, theoretically insurmountable.

Imagine if a cheap submarine somehow managed to get past an aircraft carrier’s defenses and sink it. Although this is a hypothetical scenario, it happened during a large-scale exercise, when a Swedish submarine managed to “sink” an American aircraft carrier.

A Big Surprise: US Navy Aircraft Carrier vs. Swedish Submarine

In 2005, the US Navy held a large-scale anti-submarine warfare exercise off the West Coast. As part of the training regime, planners pitted the small Swedish HSMS Gotland against the aircraft carrier USS Ronald Reagan and her battle group.

Much to everyone’s surprise, though perhaps not her crew’s, HSMS Gotland was able to penetrate the anti-submarine layers protecting the carrier, including helicopters and destroyers explicitly searching for the submarine, and make several simulated torpedo “hits.” Planners concluded that USS Roland Reagan would have sunk or suffered severe damage if the exercise had been real.

To make matters worse, the HSMS Gotland, a small diesel submarine, was able to replicate its feat multiple times over the course of two years, causing alarm in the naval community. If a small, inexpensive submarine could sink a multi-billion dollar aircraft carrier protected by multiple layers of anti-submarine warfare, could Chinese or Russian submarines cripple the U.S. Navy in the event of a conflict?

Gotland class submarine

The Swedish submarine cost only $100 million, a fraction of the $4.5 billion USS Ronald Reagan cost, not counting the price of the entire battle group. Also, diesel submarines may be cheaper than nuclear-powered ones, but they are much more nervous and can stay underwater for a shorter period of time. However, HSMS Gotland used Stirling engines, invented in the early 1800s, which made the submarine almost completely silent to enemy sonar and therefore invisible even to an aircraft carrier.

The success of the Swedish submarine was so profound that the United States Navy leased it to test how to counter such threats.

As near-peer competition with China increases and Beijing seeks to assert its power in the Indo-Pacific, primarily through naval power, the lessons of the diminutive HSMS Gotland are even more relevant.