| The Virginia-class attack submarines are allocated | | | | through decommission and it was decided by |
| to replace the ageing Los Angeles class of | | | | Congress and the US Navy to accelerate delivery |
| submarines which have housed a substantial | | | | of the Block III submarines. |
| portion of America's mobile, nuclear arsenal. They | | | | Part of the acceleration and cost-control |
| are designed for extremely long-mission durations | | | | measures implemented has involved taking |
| with minimal time spent in port for replenishment | | | | existing technology and developments from other |
| and 15-year maintenance cycles in dry dock. | | | | projects and redesigning them into the Block III |
| In every sense of the phrase, they are designed | | | | Virginia-class boats. For instance, the bow design |
| as mission critical platforms for America's defense. | | | | of the Block III boats is taken from the |
| The Virginia-class were chosen as the next | | | | Ohio-class submarine fleet while jet-pumps have |
| generation of US Navy attack submarines after a | | | | been utilised for decreased cavitation and for |
| lengthy consultation period and narrowly won the | | | | much quieter running even at higher speeds. The |
| procurement process over the more expensive | | | | Virginia-class boats are reportedly quieter at 20 |
| Seawolf class. Cost savings of an average $200 | | | | knots submerged speed than previous classes at |
| million are envisaged with the Virginia-class | | | | 7 knots. |
| bill-per-submarine coming in at $1.8 billion (in Fiscal | | | | DARPA has overseen the Tango Bravo initiatives, |
| Year 2004). The actual build cost is now thought | | | | which have also resulted in the adoption of |
| to be around $2.5 billion per boat though | | | | externally stowed and deployed weapon systems |
| cost-saving measures are in force to secure | | | | (particularly torpedoes). Management systems also |
| pricing for the US Navy. | | | | allow for control of the electromagnetic signature |
| The cost-saving measures have focused on the | | | | due to electrical and mechanical systems as well |
| concept of "Tango Bravo", or Technology | | | | as the hull, all of which increase the stealth |
| Barriers, which have presented themselves as the | | | | characteristics of the submarine. There is also |
| Block III vessels have moved from drawing board | | | | increased automation of crew activities which |
| to shipbuilding yard. The complicated nature of the | | | | reduce the workloads of the crew and increase |
| submarines combined with escalating costs and | | | | operational efficiency. |
| project management issues, and the political | | | | At the heart of most of these Tango Bravo |
| decision to place the construction orders with two | | | | innovations lies the pumping systems which utilize |
| contractors (GD Electric Boat and Northrop | | | | a wide-range of pump models, including centrifugal |
| Grumman - the only two yards capable of building | | | | pumps, screw pumps and highly engineered |
| nuclear submarines in the US), have all placed | | | | valves. These systems must be capable of |
| considerable strain on cost control and meeting | | | | operating with extremely long maintenance cycles |
| delivery schedules. | | | | in the most demanding operational environments |
| The importance of cost control in a budget | | | | conceivable. Many of the Tango Bravo systems |
| constrained, economic environment is all too clear, | | | | cannot operate without highly advanced pump and |
| however the strategic importance of delivering | | | | valve systems to manage and operate them, |
| vessels to schedule is more important. The Los | | | | from silent propulsion to weapon deployment. |
| Angeles class is already one quarter the way | | | | |