The Royal Navy's stealth sub can stay submerged for 25 years

Rex Features

The Royal Navy's stealth sub can stay submerged for 25 years - We Are The Mighty: Submarine technology has come a long way since the early days of the diesel-powered silent killers. Now these billion-dollar ships are engineering marvels.

The UK's submarine fleet conducts some of the most secret missions in the Royal Navy. For that, it requires the quietest ships ever built – the Astute-class submarine. Capable of tracking enemy ships, listening in on foreign communications, tracking vessels and aircraft, delivering special operators, and more. It can even launch a volley of Tomahawk missiles while submerged.

And no one would ever see it coming.

The seven Astute-class subs will soon be the only attack subs in the Queen's fleet. The only other submersible ships will be tasked with carrying the UK's sea-based nuclear arsenal. The rest of the Royal Navy's subs will be decommissioned by the time the Astute and her sister ships are all in the water.

Engineers at BAE were tasked with something nearly impossible: silencing a 7,400-ton nuclear-powered warship with 100 British sailors on board. They had to reverse engineer how noise would be emitted from the ship, trace them to the source, and dampen it. And since the submarine would be completely vulnerable while completing its mission, the engineers also had to protect the ship from a torpedo impact, one that would be designed to break the ship's back.

And yes, the Astute can take a direct hit from a modern torpedo.

But the Astute and its class are still under construction. There have been a few mishaps, only a couple of those are due to engineering. An accident ran the ship aground a couple of years ago, causing minor damage. Since then, leaks and corrosion have been reported. Engineers working on the ship say since each ship costs $1 billion, they can't make a viable prototype – it's too expensive. But the lessons learned in the trials are being incorporated into the construction of the other ships.

Other factors that keep the ships quiet are the acoustic tiles that cover the ship's exterior, the ultra-quiet rafts holding the pumps for the seawater that cools the ship's reactor, and a diffuser that keeps the ship's extra carbon dioxide from bubbling to the surface. The ship also has its magnetic signature reduced, and its wake is designed to be minimal.


Astute Class SSN: Details