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Ohio Replacement Program - District of Columbia Class SSBN

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  • #31
    Originally posted by Real_Clear_Defense

    Don't Even Think About Redesigning the Columbia SSBN
    by Frank Miller
    31 March 2022

    A recent article (link) asserts that the design and missile tube capacity of the new Columbia-class SSBN are unsuited to the new world of two nuclear-armed potential adversaries and that both should be revised. Specifically, the authors argue that the decision for the Columbia-class to carry 16 rather than 24 missile tubes was based on faulty and unreasonably optimistic arms control assumptions. As a result, they call for modifying the submarine's design to increase the number of missile tubes in order to boost U.S. warhead numbers. While I believe that the emerging security environment will inevitably require increases in the U.S. deterrent arsenal, this particular argument needs correction as to its history and its technical arguments.

    To begin, apart from the requirement that a fully modernized U.S. nuclear Triad envisioned by the Obama Administration conform to the limits of the New START treaty, arms control did not play a role in the design of the Columbia class. As a result of the Administration having decided (correctly) to maintain a full Triad, the number of SLBM tubes allowed under New START was derived from the number of ICBMs and bombers it had opted to retain. The number of total SLBM tubes having been fixed; the next decision was to determine how many SSBNs carrying how many missile tubes per boat would best meet national requirements.

    The two factors which figured most heavily in the design decision were the overall length of the submarine and a desire to maximize the number of SSBN hulls. I was a member of an ad-hoc group formed to advise Strategic Command on the issue; we were informed by the Navy that several new technologies in Columbia’s design, such as the new electric drive propulsion and other new equipment, had added to the submarine’s length. As a result, a Columbia SSBN fitted with 20 or 24 missile tubes would have been too long to be accommodated by the SSBN force support infrastructure, principally the dry docks and the submarine piers. This strongly suggested that a 16 tube Columbia-class was the preferred outcome.

    Notwithstanding that technical judgment, there were still officials in the Defense Department who were prepared to enlarge the infrastructure to accommodate a 20 or 24 tube Columbia; this was driven by a desire to procure the smallest number of new SSBNs possible. A 24 missile tube Columbia SSBN would have resulted in a force of only 8 SSBNs. The advisory committee, cognizant of survivability considerations and other aspects of SSBN operations, argued strongly for the largest number of Columbia hulls possible: with 16 missile tubes, this meant a force of 12 new SSBNs, a 50% increase over a 24 missile tube force.

    Combined with the technical/infrastructure argument, the twelve boat force armed with 16 missile tube positions carried the day. Several years later, the 2018 Nuclear Posture Review, recognizing the increasing uncertainties associated with an emerging two-nuclear peer world, amended the procurement guidance by calling for “a minimum of 12 Columbia SSBNs”, which is where the program stands today (unless it is modified by the forthcoming Biden Administration NPR).

    Having stated their bias, the article’s authors then offer two conflicting recommendations: “assess the feasibility of program or design modifications to [follow-on] Columbia SSBNs," but “any changes that are made must not delay delivery of the Columbia program ."A 20 or 24 missile tube Columbia SSBN will require an accelerated missile tube delivery rate to maintain the Columbia-class build cadence. If the industrial base cannot meet the accelerated missile tube demand, then any modified Columbia SSBN deliveries would be delayed. Any attempt to redesign the boat will increase program costs from redesign and additional construction to add more missiles tubes. The Navy will also have to modify submarine infrastructure to accommodate a longer and deeper draft SSBN, adding significantly to program cost and time. Lastly, a Columbia-class design change of this magnitude could potentially impact the design and engineering of SSN(X), which will commence in the near future.

    Solving the potential inadequacy of the existing force against both near-term and medium-term future requirements is a real issue. But for the next ten-to-fifteen years, this can only be resolved by examining other ways to enhance legacy Triad legs to augment the existing force. For the longer term, building more than 12 Columbia SSBNs is part of the answer.


    Franklin Miller served for three decades as a senior policy official in the Pentagon and on the NSC Staff


    • #32
      My understanding, perhaps incorrect, is that New Start allows variable distribution of deterrent resources among the three legs of the Strategic Triad, and that within that variable distribution the United States has declared that it will not deploy more than 240 SLBMs at any time, which means a maximum of 240 VLS tubes on SSBNs loaded with D5 SLBMs, regardless if in port or at sea, but not including any emptied SSBN.

      Do the simple math... 240 SLBM in 12 SSBN is 20 SLBM per SSBN, not 16. And with 16 VLS tubes per Columbia SSBN, 240/16 is 15 SSBN fully loaded with SLBM, not 12 SSBN, and that doesn't include any emptied SSBN in for repairs extensive enough to require offloading the SLBM. Perhaps they may be planning to expand numbers beyond the 12 Columbia SSBN. My own opinion is that they may find need for 11 for the Indo-Pacific fleet, and 4 for the Atlantic fleet, and 1 empty in the shipyard, 16 Columbia SSBN in total. Add 2 Columbia based SSGN to the numbers. That gets to 18 of the big boats, SSBN and SSGN, rather than 12.

      It would be less expensive to add 4 or 8 GN-like shorter depth tubes to the BNs by adding 1 or 2 modified Columbia/Dreadnaught CMC modules to add 4 or 8 CPS MACs with 3 CPS missiles each, adding 12 or 24 CPS hypersonic missiles to the 16 SLBM carried on each Columbia SSBN, and build 16 of those larger SSBN, 15 loaded and 1 emptied and in the shipyard for tech insertion upgrades and repairs. But they won't be doing that.

      edit: They wouldn't have to fully flesh out the addition, but rather as a backfit program they could later add hardware and software mods to enable the added capability. Finishing the internals later would not be as extensive an effort as would be the later insertion of a hull extension plug to a completed submarine. Also, they could have two variants, a Block-I Atlantic variant without the added CPS capability, and a Block-II IndoPacific variant with the added CPS capability (adding 1 or 2 CMC modules to add 4 or 8 tubes, to add 12 or 24 CPS missiles to the 16 D5 SLBM), so the longer subs could be built after building the shorter subs, allowing more time to accomodate the changed design.
      Last edited by JRT; 27 Jul 22,, 05:27.


      • #33
        One question: the increase in vessels...will the Navy have the Sailors to manthem?
        “Loyalty to country ALWAYS. Loyalty to government, when it deserves it.”
        Mark Twain


        • #34
          Originally posted by Albany Rifles View Post
          One question: the increase in vessels...will the Navy have the Sailors to manthem?
          If they decide to build more of the big subs, they will need more crews and support personnel and infrastructure, but they would have a long time to solve that personnel problem. They could not much increase the number of subs in the near term. They would first need to build more capacity in the industrial base.

          If they decided to build only a few more additional subs, but with longer length, it would have less effect in added capacity in the industrial base, and I suspect that increasing the length of the new SSBNs to add a CPS hypersonic weapons system would not add big numbers to crews or support if the added system interfaces to the submarine's BYG-1 system with some added software modules and the hardware (missile interface, tube interface, hatches, etc., adapted to the CMC module) carried over from the VPM from Virginia block V.

          Reportedly, first delivery is scheduled for 2027, twelfth delivery in 2042, and first deployment in 2031. They could add more builds on the back end of that, two decades from now, but if they wanted to add more sooner by increasing the rate of production, they would need to expand industrial capacity, and that isn't instantaneous. I don't think they could do that until after the first several builds, toward the middle of the effort.
          Last edited by JRT; 11 Jun 22,, 00:55.


          • #35
            Originally posted by Seapower

            Navy SSBN PEO: Data Clearly Supports Building More than 12 Columbia Subs

            by Richard R. Burgess, Senior Editor
            09 June 2022
            Seapower - the official publication of the Navy League of the United States

            ARLINGTON, Va. — The admiral in charge of building the Navy’s next-generation nuclear-powered ballistic-missile submarine said there may be an advantage to building more than the 12 planned boats.

            “I have clear data that says, ‘It clearly makes more sense to have more than 12 [Columbia-class SSBNs] to meet the current requirements that [U.S.] Strategic Command has defined for us,’” said Rear Adm. Scott Pappano, program executive officer for Strategic Submarines, speaking during a June 9 Hudson Strategic Forces Seminar in Washington.

            “I have the data that will show the risks of what the current program of record is, and here is how those risks are mitigated if I go to 13 or 14 or 15 or 16, how that affects those requirements,” Pappano said. “It’s probably a late ‘20s decision, sometimes before the end of the next block that we are doing.”

            The current U.S. Nuclear Posture Review defines the requirement for “at least” 12 Columbia-class SSBNs.

            Pappano said building extra SSBNs would not be a technological problem but a matter making decisions early enough to keep submarine programs on schedule.

            “It’s really getting both the cadence for the Columbia class and to be able to get back on cadence for Virginia [attack submarine],” he said.

            The contract for building the first new SSBN, the future USS District of Columbia, calls for delivery 84 months of formal program start. Pappano’s goal is to deliver the boat in 78 months. With the construction started during the COVID-19 pandemic, construction “got a little bit slower start than we wanted” so it was lagging slightly behind 78 months but still ahead of the required maximum of 84 months.

            “It’s not only delivering [the lead ship] on time … but we’ve got to get the cadence right for the rest of the class,” he said. “We have to be delivering Columbia class at a one-per-year cadence [in fiscal 2026].”

            With the future USS District of Columbia and USS Wisconsin under contract, the Navy originally had planned to build the next three boats in the next block to get economic order quantity of the SSBNs and the Virginia-class SSNs.

            “We’re working right now with our stakeholders to include five boats in the second block,” he said, to make that block buy in 2026 and “at least a five-ship block” for the third block.

            The 12 Columbia-class SSBNs will be replacing the 14 Ohio-class SSBNs that each are scheduled to be retired at 42 years of service. The first of the Ohio SSBNs to be retired will be inactivated in 2027.

            “There is going to be a period of time [for] much of the ‘30s we have to have 10 ships ready for sea, out of a depot period, and we’re going to have exactly 10 for a lot of that time,” Pappano said. “If you look at it month by month, there are periods where we might dip below nine.”

            He said the Navy is looking at starting advance procurement for each boat “a little bit early… about six monthsish” for Columbia boats two through 12, a plan supported in the 2023 budget request.

            The first Columbia-class SSBN is required to be on patrol in the first quarter of fiscal 2031. Pappano said the Navy is looking at squeezing more service life out of five Ohio-class boats with short service-life extensions of the boats that are in the best condition. The admiral said that fiscal 2026 would be the time to make the decision, with the first Ohio extension completed in fiscal 2029, and each taking three years.

            Pappano said one advantage of extending an Ohio-class boat is during the 2036-2039 time frame, a submarine will be needed to test-launch the D5LE2 version of the Trident ballistic missile in support of the Strategic Systems Program. This would avoid having to take a submarine off the strategic deterrence patrol cycle to test the missiles.


            Pappano: Studying ‘Shortish’ Life Extension of Ohio SSBNs as Risk Mitigator

            by Richard R. Burgess, Senior Editor
            13 May 2022
            Seapower - the official publication of the Navy League of the United States

            ARLINGTON, Va. — The U.S. Navy admiral in charge of procuring and sustaining the Navy’s ballistic-missile submarines (SSBNs) said the Navy is studying possible short service-life extensions of some Ohio-class SSBNs and even the Ohio-class guided-missile submarines.

            The Ohio-class SSBNs are scheduled to be replaced by the Columbia-class SSBNs now under construction. The first Columbia SSBN is scheduled to be on patrol in fiscal 2031 in order to maintain the undersea leg of the nation’s nuclear deterrent force. The margin available in the schedule for the Columbia program is tight.

            “Because it is the prudent thing to do, we are evaluating potential — not class extensions — but individual hull extensions for up to five of our Ohio-class SSBNs,” said Rear Adm. Scott Pappano, the program executive officer for strategic submarines, speaking May 12 in a webinar of the Advanced Nuclear Weapons Alliance Deterrence Center.

            The Ohio-class SSBNs were built for 30-year service lives, which were lengthened to 42 years through an extension program.

            “It’s very hard to get past 42 years,” Pappano said. “We’re going to at least evaluate that in the background. The first time we’d actually have to start thinking about doing that — to actually do one — would be in the FY29 time frame. So, we’re doing the evaluations right now on what it would take to do a ‘shortish’ repair availability to extend those ships for a couple of years as a risk mitigator, if need be. My goal is to not have to do that, but we want to understand the opportunities and risks associated with that short extension of the Ohio if we need to go do that, depending on what the world situation looks like at the end of the ‘20s and into the ‘30s.”

            The admiral said the Ohio class has been upgraded with a modernized Strategic Weapon System and COTS (commercial-off-the-shelf) systems and sensors.

            “That class is doing very, very well,” he said.

            Pappano also said that “as part of that we’ll also evaluate the SSGNs (Ohio-class guided-missile submarines) right now. That’s a bit more of a challenge because those ships are operated vigorously than the SSBNs are in the current roles they have right now, but we will continue to look forward to doing that.

            “Eventually, the Virginia-class (SSN) VPM (Virginia Payload Module) capability will supplant much of that (SSGN) missile inventory,” he said. “Until that comes online, we want to make sure we have the missile shooter capability in the SSGNs for as long as we can, but it’s going to be a delicate balancing act of maintaining the current SSBN fleet versus extending the SSGN fleet. One of the things we’re looking at right now as we go forward is to make sure we provide as much capability to the warfighters as we can at the right amount of risk.”


            I do not agree that Virginia with VPM "will supplant much of that SSGN missile inventory". Four SSGN with 22 VLS tubes each, with 7 T-LAM in each VLS tube, for 154 T-LAM in VLS per boat, 616 T-LAM in VLS in total in four boats. Virginia block III and IV have two large VPT tubes (similar diameter as VPN in some of the upcoming block V, but shallower tube depth) forward of the sail, and those can be loaded with 6 (not 7) T-LAM each. After the first one or two Virginia block V subs they will add a VPM plug to block V which adds 4 more tubes aft of the sail which can be loaded with 7 T-LAM each, in addition to the 2 forward which can be loaded with 6 T-LAM each, for 28+12=40 T-LAM in total in VLS per SSN. 616/40=15.4, which if it happens will be a long time from now at a couple of SSN per year, considering they have not yet built the first one.

            Aside from those T-LAM, we will be adding CPS missiles to the equation, with different capabilities, and different applications in different missions.

            I think that it may be recognized that we need more GN/VPM size VLS tubes than is suitable for the 34 foot beam Virginia SSN platform and is better suited to the 43 foot beam Columbia SSBN platform, as it has been for the 42 foot beam Ohio SSBN/SSGN platform.

            And although the Biden administration killed funding for the Nuclear-Armed Sea-Launched Cruise Missile (SLCM-N), I expect these may eventually return, maybe under a different program name.
            Last edited by JRT; 15 Jun 22,, 20:47.