Today, the submarine is the most powerful asset in modern warfare and increasingly, nations see these silent leviathans of the deep as the ultimate military asset in a hi-tech world where satellites can track planes, ships and almost anything – except a nuclear boat. Submarines can remain at sea for months, sit in the dark depths of the oceans listening for other submarines and be ready if ordered to launch a ballistic missile strike. Their covert capability allows them to patrol anywhere without trace generating an aurora of psychological anxiety for their foes who never know where they are or what they are doing. From the United States, Britain, China, France, Russia, India, North Korea, Iran, Japan, Turkey, Greece, Italy, Egypt, Pakistan, Sweden, Peru, Spain, Poland, Argentina and South Africa…