Trish Lorenz reporting from Portugal: The Portuguese navy is one of the oldest in the world, with a history that ebbs and flows back to the 12th century. As the tides have changed so have its responsibilities, with clever diplomacy and humanitarian missions now as much of a priority as protecting the nation in combat and safeguarding its vast territories. Life on board a submarine, in particular, isn’t easy, but they come complete with a healthy dose of camaraderie – and a commitment to an essential maritime service.