VIGILANT Back – the Strategic Submarine VIGILENT has recently returned to Faslane following a three year overhaul (Long Overhaul Period - Refuel in the jargon), the work package was an enormous engineering task, with the submarine emerging as effectively a new boat inside, with 2.2 million man hours involved in the overhaul under a £350m contract with Babcock Marine at Devonport.     A new reactor core  which provides the power for the vessel was fitted meaning that the VIGIGENT will be able to function until the end of her operational life without ever having to refuel again.  The VIGILENT will now complete final preparations for Demonstration and Shakedown Operations (DASO) including the firing of a dummy TRIDENT missile on the US Test Range before returning to the operational Deterrent Patrol cycle.