Military submarines are out there, lurking under the water, ready for action, but how long can they stay down there? It's longer than you might think.

Only the U.S. Navy can match these underwater warships. As noted by naval analyst H I Sutton, the Astute-class subs are the only ones outside the U.S. Navy able to launch the Tomahawk, a ...

In terms of capabilities, as an Astute-class submarine ... Agamemnon will bolster Britain’s underwater capabilities, ...