when were submarines first used in world war 1
U-boat On 5 September 1914, HMS Pathfinder was sunk by SM U-21, the first ship to have been sunk by a submarine using a self-propelled torpedo. On 22 September, U-9 sank the obsolete British warships HMS Aboukir, HMS Cressy and HMS Hogue (the "Live Bait Squadron") in a single hour.
Ohio-class submarine The US Navy has a total of 18 Ohio-class submarines which consist of 14 ballistic missile submarines (SSBNs), and four cruise missile submarines (SSGNs). The SSBN submarines are also known as "Trident" submarines, and provide the sea-based leg of the U.S. nuclear triad. Each SSBN submarine is armed with up to 24 Trident II submarine-launched ballistic missiles (SLBM). Each SSGN is capable of carrying 154 Tomahawk cruise missiles, plus a complement of Harpoon missiles to be fired through their torpedo tubes.