Not much margin there, you will also need to know which one is the most knackered (not to refuel that one... it is not necessarily the time order even though to assume so would be logical).shark bait wrote:Vanguard - 2028
Victorious - 2030
Vigilant - 2032
Vengeance - 2034
So? Do the middle two, prior to 2028, let Vanguard drop off in natural sequence and swap Vengeance one for one with the first Successor?
The DID story from April this year (includes promises that the new Mk.2 reactor won't need refuelling, but what was the time horizon being looked at then as opposed to now?) sets a precedent of 42 months per boat:
"Britain has announced a GBP 350 million (about $560M), 42 month contract for a 4th “complex overhaul” of its 15,000t SSBN Vanguard Class external link nuclear missile submarines. HMS Vengeance will require about 2.5 million man-hours of work, including installation of a new Mk.2 nuclear reactor core. As of March 2/12, the submarine was at Devonport ready to dock down, and will remain in dry dock until flood-up in late 2014.
HMS Vengeance is the last of the UK’s 4 SSBNs submarines to undergo the Long Overhaul Period and Refuel (LOP-R)."