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An SSK Trident Solution

June 28, 2010
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Realizing I said earlier we probably don’t need a conventional powered fleet ballistic missile submarine any time soon, the following proposal was too hard to resist. I came across this idea while browsing through my tattered copy of National Defense, by  James Fallows. This 1981 book at the time had a profound impact on the Military Reform Movement, though sadly did very little to reform the Pentagon, as we see the same budget troubles brought on by over-ambitious and too complicated weapons programs coming back to haunt us (one reviewer said in 2003 “NOTHING HAS CHANGED since this book was published in 1981“) . Sadly, there is no restored economy we can count on to save us so we have to return to good ole common sense reform. Here is one such timely approach within the book concerning the nuclear deterrent:

Since the ultimate propose of the submarine is to survive, it makes sense to reverse the thinking that has given us the Trident and move instead toward a diversified fleet that includes smaller, cheaper, harder-to-find, more numerous submarines. A more dramatic solution, proposed by Richard Garwin of IBM and Sidney Drell of the Stanford Linear Accelerator Center, is the “shallow undersea mobile” system, or SUM. This would be a fleet of small submarines, each of which would carry two MX-type missile in capsules mounted on its hull. The submarines would be powered by batteries or fuel cells, and therefore would be even quieter than nuclear subs. They would require a crew of only fifteen or twenty men. Because the range of the MX missile is so long, the small submarines would need to travel no farther than a few hundred miles off the east and west coasts, instead of going into the open sea. They would operate a large enough operating area to prevent the Soviet Union from simply “barraging” the coastline with nuclear weapons and destroying the submarines, but the subs would still be close enough to shore to have good communications, with virtually no “dead time” as they travel to their stations. The submarines with its missiles could be as small as 1100 tons, as compared to the 18,500 tons for the Trident. According to Garwin and Drell, the German Navy has operated a fleet of 500 tons submarines for 10 years.

Interesting that the German subs were brought up, since recently the Bundesmarine discarded six thinking them not useful enough for the costs. But giant warships are “economical”, so we are told, also vanishing quickly and increasingly unaffordable. Naturally with MX now dead, we would return to the Trident alternative, especially with its latest version so much more capable than the first gen from the 1980s.

*****

22 Comments leave one →
  1. Heretic permalink
    July 1, 2010 9:34 am

    A Virginia-based evolution could be done for an SSBN, but in order to house the Trident D5 missiles, you’d need modify (ie. elongate) the ship’s sail in order to fit them. The Trident missiles are 44ft tall, and the hull diameter on a Virginia class is 34ft. Stretch the sail, with a dedicated hull section underneath it, and you can “easily” fit some 4 (or so) Trident missiles in a single file line behind all the masts and periscopes on the forward end of the elongated sail. This would place the Trident missiles roughly amidship in an elongated Virginia SSBN.

    Still means that for a vertical launch tube, a Trident boat is going to easily be bigger than 8000 tons submerged … nuclear or no.

  2. Anonymous permalink
    June 30, 2010 5:53 pm

    Before anyone jumps on me for saying that an SSBN would be harder to find than an SSB, I am aware that diesel submarines are quieter than nuclear. That is an example of tactical stealth however, only useful if you get close to the sub. Diesel submarines lack strategic stealth however, because of their short range. Nuclear subs on the other hand have virtually unlimited range, giving enemies a greater volume to search and less chance of finding them. (And, if it comes to that, nuclear subs also have plenty of tactical stealth).

  3. Anonymous permalink
    June 30, 2010 5:38 pm

    Probably not, given the small size of the proposed SSB (not SSK) and its payload of only two missiles. See my previous post on an SSB based on the Scorpene. A modified Virginia would be able to carry at least ten or twelve ballistic missiles, so even if the Virginiad were five times as expensive they would still be able to carry at least as many missiles/$ as an SSB as well as being longer range/endurance. SSBNs would also be much harder to find than a short range SSB.

  4. Mike Burleson permalink*
    June 30, 2010 12:55 pm

    “If they each carry too few, then you have to buy a lot and it starts to get really expensive.”

    So we are back to the SSK?

  5. Anonymous permalink
    June 30, 2010 6:41 am

    But how many missiles can each modified Virginia carry? If they each carry too few, then you have to buy a lot and it starts to get really expensive.
    On the plus side, though, modifying an existing class does make more sense (and is faster/cheaper) than designing an entirely new SSBN.

  6. Distiller permalink
    June 30, 2010 2:50 am

    @ Anon:

    Not taking existing Virginias of course. Mod the hull, stretch’n’hump. Should be cheaper than starting a completely new class of boats, or build Ohio II (since those are pre-CAE). But this really depends on the availability of a new, smaller SLBM. With the UGM-133 there will be no small SSBN. And for cost reasons this new SLBM has to be linked with the LGM-30 replacement. To work the costs have to look like this: New (joint) missile + modded Virgnia <<<SYSTEM LIFETIME COSTS<<< old missile (Trident) + new SSBN class. It's hard to figure, but I think R&D for a new missile and a completley new SSBN would be around the same (~15 billion USD?), but a modded ballistic Virginia would be about half the unit cost of a completly new SSBN. And if done clever (hmmm …) there are load-balancing opportunities between SSN-Virginias and SSBN-Virginias, enabling a steady and flat replacement of Ohios without a big spending hump. Combined built rate for SSN/SSBN Virginias should be 2.66 annually.

  7. Scott B. permalink
    June 29, 2010 7:10 pm

    Mike Burleson said : “Precision trumps firepower.”

    Nuclear deterrence is all about creating zero-sum situations that force opponents to avoid the worst possible outcome from their point of view, i.e. end up with losses that equal or exceed their gains.

    As a result, as Anon pointed out earlier, nuclear deterrence requires a enough firepower to be effective. Unless this threshold is met, deterrence will fail, no matter how much precision you have.

    I also find it quite strange that you may in this specific case advocate quality (precision) over quantity (firepower), whereas a recurrent theme developped on the blog is that quantity is generally more important than quality.

    Perhaps you could further elaborate on this apparent contradiction ?

  8. Anonymous permalink
    June 29, 2010 6:11 pm

    Hmmm…But is modifying a Virginia to carry SLBMs more cost efficient than the Ohios? I personally have my doubts. Also, don’t forget that any Virginia you modify for SSBN duty is one less you can use for SSN duty.

  9. Distiller permalink
    June 29, 2010 1:16 pm

    @ Heretic:

    Agree. Like I said before – a new missile is needed. Max 30ft high to fit into a (modded) Virginia hull, and for 4 MaRV + decoys.

  10. Heretic permalink
    June 29, 2010 12:41 pm

    A Trident D5 is ~44 ft tall. If kept entirely within the pressure hull, that means a silo that’s somewhere on the order of ~45-50 ft tall … which means a cylindrical diameter of ~50 ft (~15.25m) for the submarine.

    The optimal length:width ratio for albacore hulls for submarines is (iirc) 10.5:1. This would then imply a ~525 ft (~106m) length. A purely cylindrical volume of ~7.625m radius and ~106m length results in a volume of ~19,361 cubic meters … which is a submerged neutral buoyancy of ~19,400 tons (upper limit). Now … you could pull some geometric tricks to lower that volume … by putting the silos inside a sail structure for instance, allowing you to use a smaller diameter pressure hull, thereby reducing the overall length (and thus, tonnage).

    So here’s the basic problem. The height of the Trident D5 missile places some pretty firm minimum size constraints on any submarine which can carry the missile in a vertical launch position. Change that to a horizontal launch configuration and you might be able to “fit” a Trident D5 into something under 10,000 tons submerged.

  11. Anonymous permalink
    June 29, 2010 7:41 am

    By the way, how is our current SSBN fleet unlike the mobile missile systems?

  12. Anonymous permalink
    June 29, 2010 7:35 am

    A deterent is only a deterent if it has enough firepower to be effective. How many missiles do you think are necessary to be effective?

  13. Mike Burleson permalink*
    June 29, 2010 7:33 am

    Anonymous-I don’t see the need for matching the payload of the current Ohio fleet. A deterrent is a deterrent and they are planning to cut back anyway. It goes back to how big a chunk of your country are you willing to risk, knowing there are stealthy, untrackable subs out there? Precision trumps firepower.

    You could compare it to the sea-going version of mobile missile systems used successfully on land, of which the US has none.

  14. Anonymous permalink
    June 29, 2010 7:19 am

    Assuming we used a submarine of similair size (~1800 tons) and cost ($500 million) as the French Scorpene class submarine, it would be more expensive than our current Ohio SSBN fleet.

    Our current SSBNs each carry 24 ballistic missiles. We have 14 of these subs, for a total of 336 missiles. Assuming each sub costs $5 billion and has a crew of 150, then we have spent $70 billion on SSBNs and more money paying 2100 crew.

    Now to equal the number of missiles we currently have (at two missiles a submarine) you would have to build 168 SSB submarines. If each of these have a crew of twenty (instead of 31 like the Scorpene class) that is 3360 crew. Building all these submarines at $500 million each would cost $84 billion. These two factors make the SSB option much less cost effective than an SSBN fleet.

    Finally, the Scorpene class subs can only stay underwater for a little over three weeks, as compared to three months for an Ohio class sub.

  15. Hudson permalink
    June 29, 2010 2:04 am

    I mentioned something like this in an earlier thread: essentially the upright tube section of a sub without the sub, with ballast and planes for stability. It could be towed around in U.S. waters by a robot sub. Sort of a variation on the ICBM riding around on a closed track in deserted areas. Such a system might be open to theft or sabotage.

    Or a variation on the Virginias, rebuilding the Polaris subs with Trident II. I don’t think we need to replace the Ohios with like or even larger subs. It’s clear we are building down our nuclear arsenal. And I agree with Chuck Hill that we don’t want too many of these systems sitting/cruising around. What we have must be absolutely reliable and invulnerable to cyber attack. They can’t be set off by China, for example, to attack Russia so as to leave China as the last man standing.

  16. Distiller permalink
    June 29, 2010 12:08 am

    I very much support the concept of distributing the missiles over more submarines. For a (close-to-)minimum deterrence force this is absolutely critical. A Virginia-based SSBN class should follow that pattern!
    Of course the Ohios were built for first strike sneak attacks, not for deterrence.

    Re the other aspects: For one I would have put Midgetmen instead of the MX missile on such a small SSBK, as a 120 tonnes missile (weight incl launch complex) would not fit onto a really small submarine. Even two externally carried MX would require a 3000ts boat I’d say. But these are technicalities.

    More crucial is that before Trident II the SLBMs didn’t have (Trident I, Poseidon) the range to reach “Moscow” from near homeport. So the launch areas were not a few dozen hours out of homeport, but more days and days, especially with slow conventional propulsion. Basically been there before with Regulus (which also didn’t cover “Moscow”).

    In addition, such semi-mobile basing would have reduced the possible attack vectors, making the job of early warning quite easy, and potentially also ABM defence.

    Also not to forget the rather large number of Soviet SSN. With enough of them you could stalk the SSBK homeports and effectively cover them from the get-go, as their ops area would have been very predictable. Not good.

  17. Chuck Hill permalink
    June 28, 2010 11:30 pm

    To me, the fewer people who have access to the keys to nuclear weapons the better, so bigger subs with more missiles is better in that respect. But why do the subs need to be so much better than the ones we already have? If we made repeat Ohios with only marginal improvements, they should still be survivable. Virginias with a missile section plugged in the middle would probably do even better.

  18. Mark permalink
    June 28, 2010 9:46 pm

    It would be an SSB. As in Golf SSB. K denotes a hunter/killer, historically an ASW sub (versus an SS).

    Someone run the math here for equivalent number of tubes. I’m not sure I see it cost-wise. There are a few other issues too, off the top of my head, but that’s for another poat.

  19. Anonymous permalink
    June 28, 2010 9:43 pm

    If the missile tubes are attached to the sides of the hull, wouldn’t they ruin the submarine’s stealth capabilities?

  20. Mike Burleson permalink*
    June 28, 2010 9:08 pm

    tangosix wrote “,I would doubt whether two 88 tonne missiles could be fitted in a 1,000 tonne submarine’

    The author wrote “would carry two MX-type missile in capsules mounted on its hull.” So it would actually fit on launch tubes outside the hull.

  21. June 28, 2010 9:03 pm

    Hello,

    maybe that should have been S.S.B.K?

    tangosix.

  22. June 28, 2010 9:02 pm

    Hello,

    that is an interesting basing option,coastal S.S.(K.)B.N. bastions.
    However,I would doubt whether two 88 tonne missiles could be fitted in a 1,000 tonne submarine.
    Certainly they would not fit vertically in anything other than a very large boat,the Peacekeeper is 71 foot long,26 foot longer than Trident.

    tangosix.

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