Page 29 - NAVAL FORCES 03/2017

T echnology Spotlight

Warner” (SSN 785) provides the best and most construction span; and redesigning speci fic
recent example of getting ships to the fleet ear- portions of the submarine to reduce acquisi-
lier. “’John Warner’ completed its PDWP in tion cost and/or construction time. DFA began
just under six months and therefore was just with the Block III construction contract and the
eleven months from delivery to its Fleet Read­ end cost of each successive Block III subma-
iness Training Plan, proving the programme is rine has been lower than its predecessor. The
on track to turn ships over to the fleet in less Block III contract reduced contract delivery
than six years. The USS ‘Illinois’ (SSN 786) time from 74 to 66 months, and the Block IV
PDWP is planned to begin in February and is boats are doing even better – 62 months for the
currently scheduled to last six months.” first three hulls and 60 for the remaining hulls.
One of the key goals of the VCS has been The first three of the eight Block III ships (and
the reduction of total ownership costs, espe- the first to incorporate DFA changes), USS
cially Block IV, which has incorporated design “North Dakota” (SSN 784), “John Warner,”
changes to achieve better operational availa- and “Illinois” (SSN 786), all delivered early to
bility. “The programme identified technical contract, within budget, and with the same or
barriers and determined the actions required increased capability.
to extend the operating cycle from 72 to 96 One of the DFA initiatives included a rede-
months,” Stevens explained. “Decreasing the sign of the sonar. “The Large Aperture Bow Machinist Mate inspects a torpedo silo
future number of major shipyard availabilities (LAB) array, utilised on Block III and later aboard the “Virginia” class fast attack
from four to three over the service life of the submarines, uses a water­backed array vice submarine USS “North Carolina” (SSN-777).
submarine results in significant operational the air­backed spherical sonar array used on (Photo: US Navy/Mass Communication
and support [O&S] cost­savings over the life earlier submarines,” Stevens points out. “The Specialist 3rd Class Liam Kennedy)
of a ship. Reduced availabilities allow an in­ shift to the LAB array reduces manufacturing
crease in the number of deployments from 14 costs associated with the complex machining
to 15 per ship as the submarines spend less and ship construction requirements of a spher­ Starting with Block V boats, the submarines
time in maintenance periods and more time at ical array and incorporates life­of­ship hydro­ will have an 84ft long VPM inserted into the
sea” phones, further reducing maintenance costs. submarine in order to add four 87in launch
One example offered by Stevens is the The LAB array also provides improved passive tubes. Located inside the pressure hull, the
change made to the material for the propulsor sonar capabilities over earlier designs” tubes will be accessible for the crew to inspect,
to increase longevity and reduce maintenance The first ships of the class had 12 single- maintain or update the weapons. The VPM
requirements. The majority of the remaining purpose vertical launch system (VLS) missile programme is making significant progress, in-
changes were small modifications to pumps, tubes in the bow section. Current ships have cluding approval of all key decisions and ship
valves, coatings, etc. designed to increase the two large-diameter Virginia Payload Tubes specifications, with a goal of 89 percent of
periods between maintenance events. The ad- (VPTs), each capable of launching six TOM- module design complete at construction start.
ditional operating capability and O&S savings AHAWK missiles utilising the same Multiple The first payload tubes are scheduled to begin
will be realised as Block IV and later hulls are All-Up-Round Canisters (MAC) currently fabrication this year.
delivered to the fleet and during their service used on the USN’s four guided-missile sub- Stevens said that the VPM is a great exam-
lives. The USN has instituted a three-element marines. The VPTs are simpler and have fewer ple of flexible shipbuilding. “To add an 84ft
effort to reduce costs. The Design for Afforda- hull openings. The next step in the evolution module into a 374ft submarine is pretty im­
bility (DFA) initiative calls for increasing pro- of the VCS is the Virginia Payload Module pressive. It is going to really change the nature
duction to two ships per year under more eco- (VPM), which will increase the vertical launch of that ship and its capacity, firepower and its
nomical multi-year procurement; reducing the tubes on each sub from 12 to 40. overall capability.” NAFO

NAVAL FORCES III/2017 27