Royal Navy, Vanguard Class Ballistic Missile Submarine, Firth of Clyde
One of the Royal Navy's 4 Vanguard Class Submarines slips between the Wee Cumbrae and Bute on its way home to Faslane. These are the largest submarines ever built in the UK, displacing some 16,000 tons and with a submerged speed of 25kt+. They can carry up to 48 warheads each with a yield of around 100kt, 5 times that of Hiroshima.