New designs, new technologies and new weapons are shaping the submarines of the future, which are being manufactured right now, in response to global demand for more potent and flexible designs.
Old Cold War fleets are being replaced and conventional subs – smaller but still useful – that can remain underwater for weeks are being built.
Non-nuclear submarines use combustion engines that need oxygen to work. These are fine on the surface but, submerged, they must rely on battery power to operate. Depending on the battery type, submarines cannot submerge for long and need to resurface to recharge their batteries, putting them in a vulnerable position and open to detection by the enemy.
Air Independent Propulsion (AIP) is a technology which solves that problem and allows a submarine to remain submerged and relatively safe for extended periods – weeks instead of days.
First invented in Sweden in the 1990s, AIP is now used in most non-nuclear submarines by 20 navies.
A U-31 submarine goes for its first check-up run at Kiel Bay, northern Germany, in April 2003 [Heribert Proepper/AP Photo]Only a few countries can afford to run nuclear-powered submarines. Extremely expensive to produce, the reactors of these submarines allow them to stay submerged almost indefinitely.
With that in mind, attack subs also prowl the oceans, acting as a line of defence. Fast and sleek, they are designed to sink other subs, especially high-value enemy missile submarines. This endless, deadly game of cat and mouse is played out daily under the surface of the world’s oceans as each side hones the skills needed to destroy the other in the event of war.
The non-nuclear U-31 submarine is seen during a first check-up on the Kiel Bay, northern Germany in April 2003 [Heribert Proepper/AP Photo]Submarines have unique features that make them deadly, the chief one being their stealth. Able to travel undetected underwater, they can strike without warning, the most powerful among them containing missile arsenals that could single-handedly destroy a continent.
The quieter a sub, the stealthier it is. Sound is everything under the sea and billions have been invested into acoustic properties that will muffle a submarine’s engine, as well as in better hull designs which allow water to flow more quietly over the sub’s surface. These hulls are made of materials designed to absorb sonar waves – a sonic version of underwater radar – rather than reflect them back, making them more readily detectable.
Such technological advances allow subs to remain undetected but constant developments in anti-submarine technology are keeping pace – with new, improved ways to detect submarines, making them vulnerable to destruction.
The Komsomolsk-on-Amur, a Project 877 Paltus diesel-electric submarine, takes part in a naval parade marking Russian Navy Day in Vladivostok, Russia on July 26, 2018 [Yuri SmityukTASS via Getty Images]I can hear you
It is getting harder and harder to hide under the ocean. Underwater sensors can now pick up a submarine’s acoustic trail with greater ease. These sensors can be released from helicopters or planes over an area where a sub is suspected of lurking. The sensors pick up the sub’s sound profile and send the information back to the waiting aircraft. Torpedoes are then dropped into the sea with the intention of homing in on the submarine – now stripped of the one thing keeping it safe – and destroying it.
Anti-submarine warfare is as old as submarines themselves, with designers continually inventing new ways to destroy these potent weapons. Sensors are not just dropped from aircraft; surface ships are also equipped with ever more powerful and sensitive sonar suites that can pick the minute sounds that subs, despite their best efforts, end up making. Some countries have strung whole chains of sensors together across likely approach ways.
The atomic submarine USS George Washington, loaded with 16 Polaris missiles, sets sail from Charleston Harbor on its maiden voyage somewhere in the Atlantic Ocean near Charleston, South Carolina, in the US on November 15, 1960. It was the world’s first nuclear-powered ballistic missile submarine [Rudolph Faircloth/AP Photo]During the Cold War, for instance, the United States installed one called SOSUS, or Sound Surveillance System, across what is known as the GIUK gap; the area of the Atlantic Ocean between Greenland, Iceland and the United Kingdom. This was and still is the likely approach route for Russian submarines heading from their bases in the Kola Peninsula near Murmansk into the North Atlantic. This impressive system, covering hundreds of kilometres, was able to detect even the best Soviet submarines at the time, providing the US with vital information about their location and direction of travel. The SOSUS nets were extremely effective during the Cold War at picking up submarines moving in and out of the Atlantic.
Russia still uses this route. Last year, it sent 10 submarines through this gap which, while 1,500km wide, is still considered a choke point for naval vessels. In one of the biggest Russian deployments since the end of the Cold War, the exercise was designed to test whether they could be detected by NATO. The resulting detection by Western navies showed Russia that they were still vulnerable to potential destruction.
