bobbymike

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From Defensetech.org:

A New Breed of Guided Missile Sub May Be Emerging

In case you haven’t seen this, submarine maker Electric Boat is pitching the idea of building a stretched Virginia class attack sub capable of carrying up to 194 Tomahawk cruise missiles. Basically, a 90-foot plug would be put into new boats, allowing them to triple the number of guided missiles they carry. And yes, it would add $500 million or 20 percent to the overall cost of a Virgnia class boat, but it could be a relatively easy way to make up for the late-2020s retirement of the four-Ohio class boomers that have been converted into guided missile subs.

The Navy’s Submarine Force will lose about 60 percent of its undersea firepower in the late 2020s with the retirement of its four guided-missile subs, capable of carrying up to 154 Tomahawk missiles. This is happening at the same time that the number of attack submarines in the fleet is dropping because of the retiring of the aging members of the Los Angeles-class subs. The first “stretch” Virginia could be the sub that EB starts building in 2019, which would be commissioned close to the time that the first guided-missile sub retires. On the most recent Virginia-class subs, two large-diameter missile tubes located forward of the sail can launch six Tomahawk cruise missiles each. The subs also carry torpedoes. Extending the submarine to 471 feet would make room for a module near the middle with four additional tubes capable of launching seven missiles each. That would be a 230 percent jump in the number of Tomahawks that can be launched quickly, from 12 to 40.

While the new subs will have to compete budget-wise with the Navy’s Ohio class replacement effort, SSBN-X, sticking lots of missiles on one ship could save a serious amount of operations cash, as the article points out: Peter W. Singer, director of the 21st Century Defense Initiative and a senior fellow in foreign policy at the Brookings Institution, said the stretch Virginia seeks to answer a key problem that the Navy faces, the crunch in the number of submarines overall and the limits in the number of missiles they can deploy. Both problems look to be worsening in the future, he added.

“The Navy is going to face a series of tough decisions budgetwise. But all things being equal, it’s a program we have to give serious consideration towards,” Singer said Tuesday. The USS Florida was one of the three U.S. submarines that launched Tomahawk missiles into Libya last month to support a no-fly zone. One of the fleet’s four guided-missile submarines, the Florida launched a majority of its Tomahawk missiles, Breckenridge said. Typically, guided-missile submarines deploy with 105 missiles, he added. “The Navy would’ve needed eight other attack subs in theater to do what that one ship, Florida, did,” he said. Apparently, the Navy asked Electric Boat to look into the idea a couple of years ago and EB says that it could have the first modified Virgina class sub under construction by 2019.
 

sferrin

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That's actually a pretty good idea. Maybe they could have both the Virginia and this "Virginia SSGN mod" ship being produced on the same line if there is enough commonality. Make two SSNs then an SSGN, two SSNs then an SSGN. . .
 

bobbymike

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sferrin said:
That's actually a pretty good idea. Maybe they could have both the Virginia and this "Virginia SSGN mod" ship being produced on the same line if there is enough commonality. Make two SSNs then an SSGN, two SSNs then an SSGN. . .

sferrin - as for your idea you know me, faster please. If Russia and China have their collective pants in a bunch over submarine launched conventional "ballistic" missiles, how about a "trajectory shaping" hypersonic glide vehicle attached to ATK's proposed Submarine Launched Global Strike Missile in the SSGN Virginia's? We need a more time critical strike weapon than a cruise missile IMHO, We can call these "special" boats Neptune class ;)
 

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Some details about stretching future Virginia SSNs to SSGNs.

http://www.navytimes.com/news/2011/10/navy-dual-use-submarines-attack-guided-missile-101511w/

...
The idea would be to insert a new hull section with large missile tubes into the existing Virginia-class design. The exact number of missile tubes has yet to be agreed on, although most studies indicate four tubes would be optimal. The new section would be about 94 feet long and increase the length of the submarines, which today stretch 377 feet, by about 25 percent.
Two of the tubes, known as Virginia Payload Tubes, are being installed in the bows of Block III Virginia-class submarines, beginning with North Dakota, which is under construction. The bow VPTs are able to carry six Tomahawk cruise missiles apiece and replace 12 single-tube missile launchers of the original design. Although the VPTs are able to carry a larger variety of payloads, including vehicles and other gear, the bow location prevents dry access when the sub is submerged.
The new hull section, known as the Virginia Payload Module, would feature four in-line, 87-inch-diameter missile tubes able to carry a range of payloads, from Tomahawks — seven apiece, for a total of 28 — to other items that could be floated out. The VPM tubes are configured with access hatches and connectors to enable their use by special operations forces...
 

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http://www.dodbuzz.com/2011/10/24/the-navys-ssgn-crossroads/
 

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Creative

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Thanks! I was wondering where "behind the sail" the extra tubes where going to be placed.
 

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There's an article on this in Defense News. Don't see it online, however.
 

bobbymike

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Largest-Ever Shipbuilding Deal Could Grow As House Backs 10th VA-Class SubThe Navy's plan to issue its largest-ever shipbuilding contract, a $27 billion, five-year deal to buy nine Virginia-class submarines, now has a viable way forward via legislation the House adopted this week approving a new multiyear deal -- and a down payment on a 10th boat.
 

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Some Info about the "Virginia Payload Module" (VPM) Design Concept for Block V Virginia SSNs.
Links:
http://news.usni.org/2013/11/04/navy-selects-virginia-payload-module-design-concept
http://news.usni.org/2013/10/24/document-peo-subs-overview-u-s-navy-undersea-programs
 

bobbymike

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http://nationalinterest.org/feature/nuclear-submarines-americas-new-aircraft-carriers-12560

SSGN's offer a tremendous strike capability especially if built to add potentially new hypersonic and prompt strike missiles.
 

fightingirish

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Friday, 05 June 2015 10:31


U.S. Navy Awards General Dynamics $6.5 Million for Virginia Payload Module Development


The U.S. Navy has awarded General Dynamics Electric Boat a $6.5 million contract modification to support development of the Virginia Payload Module (VPM). Electric Boat is a wholly owned subsidiary of General Dynamics.




The VPM will comprise four large-diameter payload tubes in a new hull section to be inserted in Block V Virginia-class submarines built from 2019 onward.


The VPM will comprise four large-diameter payload tubes in a new hull section to be inserted in Virginia-class submarines. The section will extended the hull by 70 to 80 feet and boost strike capacity by 230 percent while increasing the cost by less than 15 percent.


The VPM allows for distribution of strike assets, giving theater commanders greater discretion in staging payload and allowing them to more easily cover widely sperated targets. The increased volume enables wide use of Special Forces and provides flexibility for the designers of tomorrow's weapons, sensors, adjunct vehicles and other potential payloads.


Block V Virginia class SSNs with VPM will begin construction in 2019 with IOC expected in 2026. They will be able to deploy a total of 28 Tomahawk cruise missiles or a wide range of future payloads.


This modification is part of an overall engineering contract supporting the Virginia Class Submarine Program. The contract was initially awarded in 2010 and has a potential value of $965 million.


The U.S. Navy has awarded General Dynamics Electric Boat a $6.5 million contract modification to support development of the Virginia Payload Module (VPM). Electric Boat is a wholly owned subsidiary of General Dynamics.




Block V Virginia class SSNs with VPM will be able to deploy a total of 28 Tomahawk cruise missiles or a wide range of future payloads.


Logo - http://photos.prnewswire.com/prnh/20140428/81320


SOURCE General Dynamics Electric Boat
 

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sferrin

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Cool. We'd only need to buy 22 of those Virginia SSGNs to match the payload of the 4 Ohios.
 

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sferrin said:
Cool. We'd only need to buy 22 of those Virginia SSGNs to match the payload of the 4 Ohios.
The total buy of VPM-equipped boats will be in the neighborhood of 20 depending on what happens to budgets for Block V and VI. The key is that those 20ish boats were getting bought anyway, whether as SSNs or in this hybrid config, whereas 4 fresh new dedicated SSGNs would be on top of the Ohio Replacement and Virginia class buys. The VPM adds about $400m in today's dollars to the cost of a Virginia, so the impact to the shipbuilding plan versus standard boats is about an additional $8.8 billion. 4 more ORPs beyond what's planned for the deterrent mission, assuming they don't cost dramatically more or less in SSGN configuration, would be about $16 billion of additional spending. It's not a perfect solution, but it's a pretty good one.
 

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covert_shores said:
How often are the Ohio SSGNs fully loaded anyway? And DDS and SF fit must reduce the load anyway?

Whether they are or not isn't the point. 1. They could be. 2. The other guy doesn't know either.
 

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Not sure why the press release says the load is 28 missiles; that's just in the new VPMs (4 MACs each with 7 rounds). There are still the two forward VPTs as well, each with 6 more Tomahawks. That puts the total up to 40 (plus whatever they stow in the torpedo room, if anything). Perhaps the original idea for 8 VPMs plus the two VPTs (56 plus 12) would have been better, but it's not really ideal because of the outer-mold-line problems it causes (the sub has to be turtle-backed, which makes it slower and probably noisier). Obviously, in a perfect world, you'd do a new design of the appropriate diameter, but in the real world, we have to make do.

The capacity of the Ohio SSGNs isn't a magical number anyway. It's just a consequence of the size of the surplus SSBNs, not a number that was based on any specific operational need. So fewer missiles is likely to be enough for most missions, and when more are needed, there should be multiple Virginias (SSN and SSGN) around to contribute.
 

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TomS said:
The capacity of the Ohio SSGNs isn't a magical number anyway. It's just a consequence of the size of the surplus SSBNs, not a number that was based on any specific operational need.

Nobody's is suggesting it's a "magical number", just pointing out the reduction in capability. Given the direction things are going with China and Russia one would think, if anything, we'd want to increase capability not decrease it.
 

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Ultimately, 20+ VASSGNs is an improvement in capability. They have similar numbers of missiles afloat, and increased dispersal is better than having all your eggs in four very large baskets.
 

sferrin

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TomS said:
Ultimately, 20+ VASSGNs is an improvement in capability. They have similar numbers of missiles afloat, and increased dispersal is better than having all your eggs in four very large baskets.

(Completely slipped my mind that the 4 VPMs were in addition to the two up front. :-[ )
 

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A couple of details to bear in mind re VPM/T: a) only six tomahawks per tube as the seventh slot will be left clear for maintenance access b) SOCOM are hoping to use them for SDVs instead of missiles
 

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covert_shores said:
A couple of details to bear in mind re VPM/T: a) only six tomahawks per tube as the seventh slot will be left clear for maintenance access b) SOCOM are hoping to use them for SDVs instead of missiles
The VPTs are the bow tubes, and when carrying a Tomahawk Multiple All-Up-Round Canister they leave the center missile out in part to accommodate access. But the VPM hull insert is designed with access to the tubes from within the pressure hull just like on an Ohio, so the tubes can carry the full MAC of 7 Tomahawk-size missiles that the current SSGNs use. To your second point, the present SDVs still use the DDS, which on a Virginia Block V I believe would mount forward of and clear of the VPM hatch doors. Future SDVs and UUVs may be deployed from the tubes instead of a DDS.
 

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Worth noting also that the forward VPTs are not accessible from inside the sub at all.

PS: It turns out that the VPM version selected actually does have a small turtleback section and a full-diameter pressure hull, without the wasp waist originally proposed.

http://news.usni.org/2013/11/04/navy-selects-virginia-payload-module-design-concept

There should be enough space to fit a DDS forward of the launch tubes -- the lockout chamber in the 774s is very near the trailing edge of the sail.

Apparently there are also proposals for additional variants based on the VPM configuration, including one with an internal SOF "hangar" with side-opening doors. Can't quite imagine cutting that big a hole in the pressure hull, but it's apparently been seriously considered.
 

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Thanks, how certain is it that the configuration claimed by that article is correct? There looks like there's room for a DDS but it's close, given the position of the hatches and SOCOM's desire to extend the DDS to fit DCS and other payloads. Maybe the DDS would have to be elevated so that the cradle clears the raised casing over the VPMs.

Side-opening doors would be like on USS Jimmy Carter. I suspect that the hangar itself is still an end-opening cylinder behind the doors but that's just my speculation.
 

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covert_shores said:
Thanks, how certain is it that the configuration claimed by that article is correct? There looks like there's room for a DDS but it's close, given the position of the hatches and SOCOM's desire to extend the DDS to fit DCS and other payloads. Maybe the DDS would have to be elevated so that the cradle clears the raised casing over the VPMs.

I'd be fairly confident that the middle image represents the approved configuration. NAVSEA should mhave had a pretty good handle on the outer mold lines by that point.
 

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