By Geoff Fein
As the Navy and its industry partners prepare to begin building two Virginia-class submarines a year, Northrop Grumman‘s [NOC] Newport News (NGNN) facility is instituting a number of efforts to lower the cost and trim the schedule in how it builds subs.
NGNN and General Dynamics‘ [GD] Electric Boat are building the Virginia-class submarines under a unique teaming arrangement.
With the first four boats under the Block I contract delivered, the two shipyards are now building Block II with the New Hampshire (SSN-778) built by Electric Boat, now at sea, and the New Mexico (SSN-779) nearing its launch date. Work is underway on the Missouri (SSN-780), California (SSN-791), and Mississippi (SSN- 782), Tom Ward, program manager for the Virginia-class construction, told Defense Daily in a recent interview.
Last month Navy Secretary Donald Winter added the Minnesota (SSN-783) to the Block II role sheet.
With six boats planned under Block II and eight planned for Block III (which is currently under contract negotiation with an expected award date later this year), NGNN is stepping up efforts to go from start to finish in five years. That effort will require process changes and improving efficiencies.
One of the more significant process changes underway is to cut the number of parts that arrive at each shipyard before final assembly by more than half, Ward said.
“Today we are pushing to get down to four (from 13). We are combining the small parts and the bigger modules, and shipping the bigger modules between us,” he said.
One of the bow modules that NGNN is going to deliver to Electric Boat went from starting out as a short module with no sail to a module with another whole section on the end of it with a sail on top of it. The section is also going to have the sonar dome over the sonar sphere, and the high frequency chin array attached to the sonar dome, Ward said.
“In effect, we have added about 150,000 hours of work to the bow module before we ship it to Electric Boat and through the improvements we are making process wise, we are basically consuming that work for the same cost we were doing before,” he said. “So both the cost and schedule have improved pretty significantly.”
Currently inside NGNN’s Module Outfitting Facility, personnel are getting ready for the Missouri, Ward added.
Not too far away, work has begun on the California and personnel are readying New Mexico for her end of the year launching.
Another effort for treating the hull has trimmed time off of the post shakedown availability (PSA), Ward said.
“We put a treatment on the outside of the ship. It requires the whole thing to be in a special climate controlled environment,” he said.
On the Block I ships the hull treatment took place during PSA. “It drove PSA to be a 12-month duration. We have now figured out a way to put that hull coating on during hull construction,” Ward explained.
“You will see us doing that on the New Mexico. We’ve been able to do it without extending the construction schedule, but it has the benefit of the PSA schedule going from 12 months to down between three and six; probably closer to three,” he said.
Taking advantage of the Navy’s capital expenditure program (CAPX), NGNN instituted a new process for handling C-seam welds, Ward said
Normally a C-seam weld takes three to six weeks and holds up a lot of other work, he said. That’s because while workers are trying to get the C-seam (Circumferential weld seam) welded, all the internal work–tying in things that go across that joint, is held up until the C-seam weld is completed.
“We’ve had an enclosure designed that is a modular thing we can drop over the C-seam. It has extendable decks on the inside, lights on the inside. It seals to the hull so that we can control the environment. It’s got enough room that we can get the automatic welding equipment installed,” Ward said. “We are employing a new series of welding equipment for this that we think will give us more error free welds.”
NGNN has another initiative in the workings. “Through the naval architecture path we’re figuring out how we can move one of the keel blocks out of the way so that we can get a full shot all the way around that C-seam at once,” Ward said, “as opposed to welding with the automatic equipment down to the block and then having to do it manually or semi- manually.”
In addition, the enclosure was designed so that workers can complete the hull coating while inside the enclosure, he added.
“If everything went well and we didn’t have any defect, we could get the C-seam weld down to the two-week time frame. A lot of the time comes not just in completing the weld, but in completing the testing afterward,” Ward said. “You have to wait seven days before you can do the test, and then after you do the test, if you find anything, you have to wait seven days again to retest it.”
So there are two things NGNN is really banking on here, Ward said. One is the efficiency that comes from applying the weld using the new equipment. But the bigger objective here, he added, is to get a higher quality weld with significantly less defect. “So that we cut that cycle down significantly between the weld and test.”
All of these initiatives actually came from concepts NGNN thought they could do on Block I, Ward said.
“We contracted for an 84-month schedule, and the last two boats of that Block, Electric Boat delivered theirs on schedule. We were two months late, largely due to a valve problem we had; otherwise that one would have been on schedule, too. But that one was 84 months, he said.
Electric Boat delivered the USS Virginia (SSN-774) and the USS Hawaii (SSN-776). NGNN delivered the USS Texas (SSN-775) and the USS North Carolina (SSN-777).
Electric Boat is at sea with the first ship of Block II, New Hampshire. “They are on track to deliver that ship in a 68-month’s schedule, so they have gone from 84 to 68. New Mexico, the ship that is pressure hull complete, we are getting ready to launch it at the end of the year. It is on a 66-month schedule. We are anticipating getting down to 64 before we get out of Block II,” Ward said.
Because of uncertainties associated with the Navy’s funding profile, NGNN was reluctant to propose a 64-month build cycle for Block III.
“So we are proposing 66, but we are anticipating that by the time we get into the fourth ship of Block III we will be down to a 60-month time frame,” Ward noted. “That was the goal all along as we started compressing the schedule…getting it down to 60 months.”
Another reason why NGNN was reluctant to propose a 64-month build cycle on the early ships of Block III is that the design is changing rather significantly to reduce the cost, Ward said. “Most of those changes hit the bow module that we are going to build.”
“We are going from 12 VLS (vertical launch system tubes) to two payload tubes, like on a SSGN. We are changing the design of the sonar array, going from a sub-safe air backed spherical array down to a pre-flooded large aperture array with significantly less cost transducers…less cost to build and install,” he said. “Overall we are implementing 94 different design changes on the Block III ships, and because this is the first time we are going to build those things, we were reluctant to anticipate a schedule reduction at the same time we were implementing significant changes.”