The Back of the Envelope: An Example of Informal Military Analysis (Part II)

Back to Part I

Would these assets be used in this fashion, however? To return to a point made several times, the primary target for weapons of this type was the Cold War Soviet surface fleet, especially its large surface combatants such as the Moskva and Kuznetsov aviation cruisers, and the Kirov class missile cruiser. Would U.S. SSNs find themselves deploying to counter this threat? I contend that they would not; that in the unlikely and unhappy event of such a conflict, with all modern U.S. SSNs are capable of fighting these assets, any submarine deployed would be able to do so. There is no reason to maintain an at-sea force with the express purpose of opposing large surface forces.

In more recently defined 'From the Sea' operations, the likely surface assets that the U.S. Navy would find itself facing are, to quote the Bottom-Up Review: "100-200 naval vessels, primarily patrol craft armed with surface-to-surface missiles."39 There would appear to be little profit in engaging these combatants with SSNs. Likewise, in the reduced scale conflicts which the U.S. Military is planning to fight (as compared to the Cold War) enemy shipping does not appear as a crucial or even sizeable target. Given the historical record of U.S. and allied behavior when intervening in conflicts, cooperative sanctions coupled with a blockade have been the method of choice for enforcing economic isolation.

Karl Lautenschläger argues that in fact a guerre de course is becoming increasingly unlikely in modern submarine warfare for a number of reasons. He points to the vastly increased amount of tonnage available for shipping, and the decreasing number of attack submarines due their increased complexity, cost and time of construction.40 Although he is examining a NATO/Pact conflict, the trends in submarine warfare which he identifies are instructive. In the case of future conflicts, the argument that Third World and regional powers will not likely have a commerce fleet to present a target, combined with his arguments, is compelling.

One method of ASuW which could feasibly be carried out by the SSN fleet is covert mining. If the U.S. decided, perhaps as an example, to mine a foreign port area, and wished to present the mining as a fait accompli, then SSNs would be able to covertly mine the target. This is a fairly expensive and low-volume method of mining, however, given that the capacity of a Los Angeles is likely to be around 40 mines or 22 CAPTOR weapons (assuming a 22-torpedo reload capability, with CAPTORs being torpedo sized and smaller mine weapons occupying approximately half of one torpedo space.) If the U.S. were to actually resort to mining foreign waters, unless it was currently occupied in a high intensity conflict with the target nation, then the act of mining would probably be a political statement as well as military action and would be done visibly, most likely by aircraft.

It appears that not only is ASuW a mission which would not require continuous boat deployment, but one which even in time of conflict would be unlikely to be of high priority for the submarine forces when compared to other mission areas such as ASW, escort and land attack. Therefore, I will assume no boats continuously deployed for ASuW purposes, with the unlikely possibility of generating missions for one or two boats in time of regional conflict only.

Land Attack

This is a mission area which has garnered much attention recently, since U.S. SSNs were among the assets which fired the opening Tomahawk TLAM shots of Operation Desert Storm. The attack submarine is now without question able to project strike power ashore. The questions that need to be asked, however, are to what degree is this useful, and under what conditions is there more utility in assigning surface assets to perform a TLAM strike, or even to assigning a CVBG to perform strike missions?

I will examine this mission area in the following fashion. First, I will discuss the disadvantages and advantages of the SSN as a strike platform. Then I will compare these characteristics to similarly equipped surface assets and the more conventional carrier land attack mission. Applying these characteristics to some hypothetical scenarios will allow us to come up with an idea of how often these missions will probably be performed by the SSN, allowing us to arrive at a rough platform requirement.

To begin with, the strike capability of an SSN is a capability which compromises its primary advantage, that of stealth. While stealth may be a useful factor in reaching a firing point, once the missiles have been launched the submarine has announced its location for all concerned to see. In addition, while each SSN can carry between eight and 20 Tomahawks, this may not be a particularly large number in the context of the desired effort. Only submarines with VLS will be able to quickly salvo more than four SLCMs; and if any opposition is expected, the launching boat will need to exit the area as soon as possible. Furthermore, disseminating mission plans to an SSN, while not extremely difficult, requires either a hard medium copy to be carried aboard, or time at periscope depth to transmit the data needed.41 Newer Tomahawks, it is true, will require less complicated mission plans, as they wil navigate using GPS rather than the data-intensive TERCOM (terrain contour mapping) system.

Tomahawk missions, thus, require significant advance preparation, both in generating the mission plan and disseminating the data. It may be possible for SSNs to generate their own mission plans, but without targeting information from the outside, this is not a very useful ability. As such, these strike missions are good only for preplanned strikes against fixed targets; there is no utility to be derived from using Tomahawks as fire support for an ongoing ground campaign. With the fluid nature of such operations, the timing and sudden targeting required by such operations are beyond the Tomahawk's capabilities.

There are, of course, advantages to launching Tomahawks from submarines. The primary advantage is surprise, purchased at the expense of the submarine's stealth. It is unlikely that a target will know that offensive action is being planned until, at the earliest, missile breakwater. That provides at the maximum of around one and a half hours' warning time for a maxiumum range flight plan.

The second advantage is that of closure. With the spread of advanced anti-ship missiles to Third World nations and likely regional aggressors, it may not be advisable to send U.S. surface combatants within sight of shore. U.S. Navy ships cruising within sight of land is really a Cold War phenomenon, as James George notes; during World War II, U.S. Navy ships closed to six hundred miles of Japan once, to launch the Doolittle raid on Tokyo, and until the end of the war they remained far outside that limit.42 It is fairly easy to fire modern sea-skimming and cruise missiles from coastal defence positions; Iraq attempted (with little success) to do so during Operation Desert Storm, firing Silkworm missiles at U.S. Navy forces operating in the Persian Gulf. Every mile a surface combatant keeps between itself and the coast is an equivalent mile reduction in the range of a Tomahawk or other land attack weapon. The range of the TLAM-D, the strategic version of the Tomahawk, is listed as 1400nm. The conventional version is listed as having a 'shorter' range, presumably due to increased warhead weight.43

Coupled to the closure advantage is the fact that a submarine, for limited strikes, can be deployed alone, allowing it to pass through hostile air force operating areas, hostile coastal defense, and hostile naval forces. It is much cheaper to deploy one SSN to make a point than to send in a group of highly visible surface assets which allow political complaint during transit (not that that would likely be a problem) and defensive military action.

When would it be advantageous to deploy SSNs to perform land attack missions? The points above allow us to delineate the scenarios. First, since the primary advantage of the SSN is its stealthy approach, two minimal criteria for deploying an SSN for this purpose are the need to hit targets deep inland and a desire to minimize the assets involved. Restrictions on doing so would include requirements to fire over a coastline difficult for submarines to access; with a long continental shelf and consonant shallow approach, for example. Also, once the requirements for the strike in terms of numbers of targets and number of weapons per target reach certain minimums, it is no longer cost effective to use submarines. We can say with reasonable certainty that once the requirement exceeds twelve missiles, it becomes necessary to either task an additional boat or to switch to surface assets with greater VLS capability. There are options to mitigate this restriction; for example, one of the retiring Ohio-class SSBNs might be modified to carry a large VLS battery of Tomahawk, on the order of 50 or more. This would require spending money to create a specialized asset, however, which is a waste when you can retain flexible assets for no investment. If the strike is to hit moving targets, or even portable targets, it would be of greater value to task a CVBG or land-based aircraft, capable of receiving targeting updates in flight or of performing terminal target identification on their own.

The types of strikes that SSNs would appear most likely to be tasked with is a limited demonstrative attack on a high value facility, or as a component of a large-scale campaign to reduce a large target set in a coordinated fashion. In the latter case, taking down an air defense system (as was done at the outset of the Desert Storm air campaign) would utilize Tomahawk strikes on central air defense targets. Once the conflict has reached this level of involvement, however, control of neighboring waters is a prerequisite, and once this has occurred tasking SSNs for this duty should really be considered in comparison to the utility of tasking additional surface assets. In cases such as this, where surface assets would have adequate protection, loading additional TLAMs onto surface assets in the theater or tasking additional surface assets solely for TLAM shooting appears to be a better solution.

It is more appropriate to consider that if an operation of this scale was attempted, any SSNs assigned to escort CVBGs or other surface groups would be available for additional 'one time' duty as a launch platform for a coordinated strike.

Small scale demonstrative strikes are, so far, the most likely and most profitable employment of an SSN as a TLAM shooter. The U.S. has performed this sort of mission only twice in the last decade, however; the bombing of Libya and the retaliatory strike on Iraqi intelligence assets. One was by land based aircraft, and one was done by surface launched Tomahawks. The shelling of Lebanese ground targets from offshore might be included in this category, but the scale and time frame of the shellings exceed the scale of a one-time Tomahawk strike from the sea.

Two instances in ten years is not a very compelling case for keeping large numbers of expensive assets in inventory, especially if assets retained for other purposes are capable of performing these missions. Given the U.S. public's increasing concern over casualties and the accuracy advantages of the Tomahawk over multiple carrier-based bombings, and the U.S. Navy's near-term lack of a long-ranged strike aircraft in its carrier air wings, the Tomahawk or an equivalent system may be reasonably expected to perform a larger share of these missions if they do arise. However, with a historical record of two missions in ten years, there does not appear to be a high enough demand to warrant keeping SSNs around solely for this purpose.

If missions were to be generated, a maximum of two SSNs would likely be assigned before the mission increased in scale enough to warrant surface forces, making the SSNs redundant. Given this, two boats available (not deployed!) should be able to take care of any contingencies of this sort. This takes into account the fact that boats on such a mission would immediately return to port after launch, for reloading; thus the number of missions they could perform per year would be greater than boats undertaking other operations. This number is based on more guesswork than I am comfortable with; however, this is the mission requirement that rests most heavily on political questions rather than operational factors. Any deployment of large-scale coordinated strikes would most likely (and should) be considered a part of a larger operation. In the event of a requirement of this size, boats would be called from port or from other duties to take part at an increased operational tempo, allowing more assets to be shifted to this task.

Intelligence Gathering

This category includes the gathering of ELINT, SIGINT and COMINT, but does not include surveillance of ports and foreign naval assets; those are explored in the ASW category. Missions in the Intel category comprise those actions taken by submarines to collect intelligence data by eavesdropping on hostile communications, telemetry and other EM and acoustic data. Missions to physically compromise enemy comunications systems, remove equipment or personnel from hostile territory or systems, and in general any mission that requires personnel to leave the boat, will be considered under the 'Special Operations' category. In general, all Intel missions would involve using the electronic systems of the boat to gather information, probably through mast-mounted sensors or from a tethered buoy, for example.

Given the ability of the U.S. to collect intelligence from satellites, aircraft and large land-based stations, the ability of the submarine to do so appears redundant. The only case which makes sense is one in which short range naval communications, or naval weapons telemetry during testing were needed. In those cases, inserting a submarine into a position to gather that information might prove useful. However, in the post-Cold War world, the problem of gathering information on enemy weapons systems is not as difficult as it once was. Discovery Channel camera crews are allowed on board Typhoon class ballistic missile submarines, and high-tech weaponry from most nations (especially the Eastern Bloc) can simply be purchased on the open market. In today's threat environment, understanding the characteristics of the weapons arrayed against the U.S. does not appear to be a challenge.

Furthermore, most of the nations being touted as potential threats to the U.S. are not maritime nations, in that most of their military communications are land based or between land and air assets. If the U.S. decided to intervene across a beach, a case might be made for listening carefully near the proposed landing point to ensure that no forces were in place to offer a defense; however, from a recent conference on Forced Entry Alternatives, a Special Operations Colonel and Marine Commander noted that one purpose of the Special Operations forces was to conduct reconaissance missions of exactly this nature.

There is, as well, the question of whether the systems in an SSN could support such operations. With space in the SSN at a premium, the boat simply may not typically have the systems required to receive and record intelligence large amouts of data. Boats modified for this duty would fall into the Special Operations category, below.

With the ability of the United States to use the other intelligence assets mentioned, I do not allocate any deployed boats for this mission group.

Special Operations

The U.S. Navy maintains a small force of submarines that have been specially modified to perform missions involving personnel exiting and entering the sub, if necessary while submerged. At present, two ex-SSBNs, SSN 642 and SSN 645, are being modified to carry the SEAL Dry Deck Shelter, a pod system attached to the hull of the submarine that stores Special Forces equipment and delivery vehicles, as well as allowing swimmers to enter and exit the submarine while it is submerged. In addition, five Sturgeon (SSN 637) class boats are listed as 'DDS Capable.'44 These boats are either permanently fitted with these shelters, or train with them; recently, at the U.S. Navy's Groton, Connecticut Submarine Base, I saw SSN 678 Archerfish with a Dry Deck Shelter installed and open.

These boats offer the most stealthy means of getting Special Forces on and off hostile shores available to the U.S. The primary question is whether or not to include them in the 'Attack Submarine' category. Although they retain their SSN designations and weapon systems, these boats would not be available for primary attack submarine missions. However, they are part of the force, and as such, the question 'how many do we need?' applies to them.

The seven boats mentioned above are not identical; the ex-SSBNs are fitted with two shelters each, as opposed to the single shelter on the 637 boats. In a large amphibious operation, there is a defensible requirement for two or three of these boats to put ashore advance reconnaissance assets. In addition, for target designation, battle damage assessment, and even search and rescue duties during a major conflict, the forces these boats could deploy would be invaluable. However, seven of them is excessive; in addition, the youngest of these seven boats was launched in 1975. I would recommend keeping the two large-shelter boats, and perhaps the youngest two 637 boats, for a retention of six of the nine available shelters while only retaining four of seven expensive submarines. These boats would eventually be replaced by modifying 688 boats instead of retiring them before the end of their service life.

Forward Presence

Some analysts have suggested that the submarine might be ideally suited for the task of forward presence missions, port calls, deliberately visible surfacings and the like, as a means of demonstrating U.S. interest and resolve. Jan Breemer notes that one such port call by a Polaris boat at Izmir, Turkey in 1963 conveyed the message that although U.S. Jupiter missiles had been withdrawn from that nation, American strategic forces were still within reach of the Soviet Union from that direction. The sinking of the General Belgrano by HMS Conqueror served to keep the remainder of the Argentine Navy in port for the duration of the Falklands conflict.45 Perhaps the knowledge that an American SSN is in the area may serve as a deterrent, to an even greater degree than a carrier which can be seen and tracked as it goes about its job.

Perhaps the most colorful example of the U.S. Navy's thoughts on the subject is the quote at the front of this paper, spoken by Admiral Kinnaird McKee to the Congress in May 1984: 'You have seen a 688 class submarine. It is a mean looking machine. They are paranoid about that big black submarine.'46 While this may be true (racial and sexual vertones aside), and submarines may in fact be useful in this category, this mission could be filled adequately by having boats on rotation from forward deployments carry out such visits.47 This would allow the same impact with no additional force size or increased tempo. Therefore I do not allocate any continuous deployment boats for this task, and do not see any need to deploy boats specifically for this purpose.


This somewhat lengthy look at American SSN tasks has left us with the following requirements for our nominal future U.S. SSN force. For Escort, three boats continually deployed with three boats needed for potential additional deployments. For ASW, two continuous and two potential; for ASuW, zero continuous and two potential; Land Attack, zero continuous and two potential; for Intel operations, none in either category, for sepcial ops, zero continuous and 4 potential (the four dedicated SpecOps boats) and for Forward Presence, zero in either. This generates a total of five continuously deployed, on-station boats with ten available for additional deployment (plus the four dedicated SpecOps).

Overlap and Ratios

Now that we have rough numbers for how many boats we would wish to deploy for each mission category, two questions arise. The first is, to what extent do these categories overlap, and does this change our planned force requirements? Second, given a requirement for a certain number of boats deployed and a certain maximum surge capability defined by the maximum possible number of temporary deployment requirements, how many boats are needed (total) in the force to meet those requirements - what is the deployment ratio?

Mission Overlap

The question of overlap should be answered first, as its answer will affect any inputs into the as yet undetermined deployment ratio to give us our final force size. I will again take each mission category in turn.

Escort missions are unlikely to overlap with any but ASW and possibly ASuW missions, as noted earlier. Boats assigned to escort CVBGs or Expeditionary Forces could quite likely find themselves performing area ASW, if their group has deployed for that purpose. They might be tasked to perform ASuW in order to keep any larger surface assets (if there were any) of the opponent away from the escorted group or force. However, these should not be taken into account as reducing potential force size, since it is equally plausible that all SSNs on escort duty should be restricted to their original function, point defense ASW of their escorted asset. Considering that I have allocated one boat rather than two as some have suggested for this function, diverting that sole boat is an unlikely option except to engage threats to the escorted asset. The only other mission it might perform while still attached is a forward presence visit; however, if its escorted asset is performing the visit, its contribution will be minimal at best and most likely it would be retained at sea to ensure a clear exit from the port.

ASW boats may see some mission overlap; they may be called upon to perform land strike missions for example, especially on hostile submarine support facilities in aid of their primary mission. The two continuous deployment boats keeping track of the Russian fleet, however, are unlikely candidates for any alternative tasking. SSNs performing area ASW to protect shipping or operations within an area might be deployed for land strike tasks if traffic was low in their assigned area, or once they had reduced the threat to a minimum.

Land attack boats, once they have completed their strikes, are capable of being diverted to escort, ASW, ASuW, intel (if so equipped) or forward presence missions, at the expense of land strike mission operational tempo.

Special Operations boats, which will have undergone modification in any case, are good candidates for intelligence gathering missions should the need arise. These boats would generally be 'available' as they are dedicated assets, unless a major Special Forces operation was under way.

It is possible that, should Los Angeles boats be converted to this capability, they might retain their VLS capability, giving up internal weapons storage for their special ops modifications. In that case, they to would be ideal 'extra' dedicated land attack boats. I am not sure the Los Angeles class has enough reserve buoyancy to accept the DDS and associated equipment and still retain the VLS systems, but it is a possibility. If a Los Angeles were to give up its 22 internal weapon reloads, perhaps even two of its four torpedo tubes and associated equipment, the VLS systems might be retained. It might well assist in balancing the boat, as non-VLS 688 boats trim visibly nose-up, and the DDS is mounted aft of the sail, although possibly not aft of the center of gravity. In any case, this would allow the four special ops boats to be used for land attack. It might even be feasible to have SEALS or other forces deployed from a special ops boat designate targets or provide targeting information to their base ship for SLCM strikes. This would likely only occur versus an adversary with no ASW capability, as the converted boats would be more vulnerable, and this would risk stranding the SEAL team(s).

In sum, it seems that while some mission overlap may exist, it should prudently be treated as excess capability rather than a means of further reducing the force size.

Deployment Ratio

This question poses interesting problems. I have argued above for a certain specific force requirement. The question of how many boats the U.S. maintains, total, is of more impact. There are varying numbers for how many boats are needed to maintain a certain number deployed; I will go over some of the figures available.

Ronald O'Rourke, of the Congressional Research Service, offers an explanation for figures such as these. In his brief, he gives Navy figures that indicate that for each boat on station, 5.7 are in transit, in port undergoing resupply, in scheduled overhaul, in training, or undergoing any of the many activities submarines and their crews perform in order to maintain their capabilities.48

At the other end of the scale, the U.S. SSBN force of Ohio submarines plans, using two crews, to maintain 66% of the force at sea at any given time to yield a deployment ratio of 1.3:1. This assumes 70 day patrols, alternating with 25 day refit and 'turnover' periods, with a twelve month overhaul every nine years.49 If we were to assume operations with one crew instead of two (as is normal SSN practice) even assuming that the submarine remained in port for one of the two 70 day patrol times, force availability would still be 33%. In that case, the deployment ratio would be approximately 3:1, much less than the 5.7:1 that Mr. O'Rourke and the Navy offer. While it is true that attack submarine patrols are less 'orderly' than SSBN patrols, and difficult to predict in terms of duration, this discrepancy is still interesting.

One explanation offered by O'Rourke is that training, which in the case of the SSBN crews can be carried out ashore with the 'off' crew, must take place with the submarine at sea in the case of SSN crews, and that this activity counts as sea time. Thus, unlike SSBN crews, SSN crews would spend this training time separated from their families. I was recently told by Cdr. Klyne, Captain of the USS Boston (SSN 703) in an interview that the Navy was having difficulty retaining personnel due to both uncompetitive salaries and more importantly a punishing operational tempo which separated them from their families for extended periods of time.

Let us look at a nominal patrol schedule for a single-crew submarine, using the SSBN system. In one complete patrol cycle (which would be a two crew cycle for the SSBN with 66% at sea time, but is a one crew, 33% at sea time cycle for our SSN) the crew would spend 70 days at sea, followed by 25 days in port while the boat is in refit/resupply. The next 70 days would be allocated to training, both ashore and at sea on short deployments, and then another 25 days would be spent in port before departing on the first 70 day patrol of a new cycle. Even if we assume the crew spends half their time during the 'off' patrol 70 day cycle at sea training, we still have 85 days of port time for 105 days of sea time. This does not appear too bad, especially given that the 105 days are not consecutive, and the number may well be less than that in any case if at-sea training is reduced. This also is assuming that the 70 day patrol allows no time for procedural training which would interfere with the boat's operational duties, which may or may not be the case.

O'Rourke states that the difficulty in decreasing the deployment ratio is in decreasing at-sea training time. In decreasing the ratio, the Navy can either decrease the amount of at-sea training, or they can decrease the amount of time SSN personnel spend with their families, which lowers the retention rate, which lowers the average experience and readiness of the force.50

One conclusion that may be drawn from this is that if tensions were to increase, and the demands on U.S. SSNs were to increase as well, there is a partial solution available to the Navy. Although the modern SSN is a long lead time item, taking several years to construct, it might be feasible for the Navy to purchase additional 'assets' by going to the 'double crew' system for its SSN fleet. This would allow an increase in boat availability without requiring new submarine construction. If it were to be done in conjunction with new construction, it would provide ready crews for submarines coming off the production line.

I do not claim that my evaluation of the possible deployment ratios is comprehensive. Due to their more stressful operating conditions, SSNs may require longer overhaul periods. Due to a more demanding environment and more tasks, it may be difficult to double-crew a SSN. However, in principle, there does not appear to be any reason that it shouldn't happen. American SSBNs, especially early models, have essentially the same capabilities as SSNs, even if they are not expected to use them. Early Polaris boats, for example, were actually attack submarines with a missile compartment inserted in the middle of the existing design. They retained all of their equipment. SSBN sailors train on this equipment; therefore, it seems feasible that SSNs might be handed off in the same fashion.

We have deployment ratios,then, ranging from 5.7:1 to 3:1. For the purposes of this analysis, I will assume the current crewing system. As compared with Navy numbers in the 45-55 range, to maintain the 5 boats continuously deployed that this paper's model requires, the U.S. would need to retain approximately 28 boats at the Navy's 5.7:1 ratio. If the Navy were to employ instead the modified SSBN schedule described above, it could (theoretically) maintain these 5 boats at sea with 15 SSNs at the 3:1 (33% availability) figure. If it were to adopt the double crewing system for SSNs and achieve the full 66% availability that the Ohio force claims (an unlikely event, but for comparison) they could maintain 5 boats at sea with a force of 9 SSNs.

Given the fact that the low ratio (3:1) is based on a single crew version of the SSBN patrol schedule, as above, there would be enough slack in the form of boats undergoing their 'off' 70-day period to generate additional boats to perform the 'potential deployment' missions as needed. These numbers above do not include the special operations boats, as they are presumed to be outside the pool of 'available' SSNs.

Although I will tend towards the Navy's 5.7 ratio for conservatism, especially as even with their ratio this analysis calls for fewer boats, I would like to add a note. In O'Rourke's study, despite the fact that he makes a convincing case for explaining the deployment ratios the Navy is presenting, it should be remembered that he is not arguing but summarizing the Navy position, as near as I can tell. As a writer for CRS, that is his brief. In addition, the numbers the Navy has presented for the SSN force (the 5.7:1 ratio) are not broken down by region as are the ratios for other ship types; rather a global average is presented with no other data.

Despite these points, however, I am unable to convincingly argue that the Navy can definately decrease the ratio below 5.7:1, and as such, will use this number for planning purposes. I have, however, offered alternative scenarios based on differing ratios.

Force Structure

After our analysis, then, we have a range of force sizes from 9 to 28 SSNs. The United States Navy, as noted in the examination of the current force, has some eighty-five SSNs presently. It could easily attain even the highest number above, simply by retiring all of its older boats and keeping, to use the Navy's requested number, the 45 newest 688 class SSNs. Since the 688 boats arrived at a rate of about 4 per year, and the oldest boat of that approximate group was launched in 1981, the U.S. SSN force would be able to stay at 45 with no new construction until 2011, assuming a 30 year boat life. This would allow plenty of time to transition to the NSSN; for example, even if production did not begin until 2011 (two years later than planned), the force size in 2011 would be: 45 688 class + 3 Seawolf class + 0 NAS = 48 SSN.

Assuming that construction of the NSSN or its successor, the SSXN, continued at a rate of slightly less than one per year to maintain a force size of 28 boats in accordance with this analysis' high end estimate, the force would transition downward at a rate of roughly 3 per year until the 688 boats had retired, at which point new construction bring the force slowly back up to 28 until it matched decommissionings. One boat per year plus scheduled refuelings and overhaul is a larger workload than the Navy is arguing for today to keep both yards (Newport News Shipbuilding and General Dynamics' Electric Boat Division) active; they claim beginning construction of one additional Seawolf in 1996 will be enough to sustain the industrial base until 1998, when the first NSSN is laid down. From then on they forsee laying down one NSSN every other year, at least until 'construction is increased to maintain a 45-ship force.'51

Another possible option is to retain 27 688 boats, fund the third Seawolf and begin NSSN production, laying down one boat in 1998, one in 2000, one in 2001, and thence one every other year. This and other scenarios are explored in Appendix 1.

This would result in a modern force, with the Los Angeles class boats retaining their VLS capability. If the exogenous special operations boats are shuffled to become older Los Angeleses as well, they would retain tube-launched Tomahawk capability if not VLS, as all the VLS boats would be incorporated into the active force. Or, perhaps better, four older non-VLS boats would remain in the main force, to retire earlier, and four VLS capable boats would be slated for conversion to special operations configurations.


I began this paper by posing the question, 'How many attack submarines does the United States need, and how should the number be determined?' Noting that the U.S. Navy has advocated a force level of 'forty-five to fifty-five boats' but has not provided evidence or analysis supporting those figures, I set out to determine a force level requirement given the current U.S. National Security Strategy.

Beginning with a brief review of the National Security Strategy itself, and the relevant conclusions that could be drawn from it, I followed with a description of the current and near future U.S. SSN fleet. Applying this to the real world, I first offered for comparison a short historical review of recent past SSN strategy and missions, and then asked the question 'what are SSNs good for?' Having answered that, I took the resulting list of mission categories and attempted to determine, given the U.S. level of involvement called for by the National Security Strategy and the Bottom-Up Review (presumably the same data the Navy used) how many continuously deployed SSNs and how many short term boat deployments would be required in each mission category.

With those total numbers in hand, I examined the number of boats the force would have to comprise to maintain those required deployments - the deployment ratio - and varying schools of thought on what that ratio actually was. Finally, armed with conservative estimates in these cases, I still arrived at a number lower than the Navy force sizing. In my analysis, a force of 28 SSNs, maximum, would be enough to meet the requirements placed upon it. At the close of the paper, I offered some thoughts on construction strategies required to maintain this force level, and in an appendix that follows I present three scenarios of what the force would look like over the next thirty-plus years if three different policies covering a range of possibilities were carried out.

There still remains work to be done. Although I shied away from attempting to develop a purely numerical model to generate force sizes, I believe that perhaps with more information models of this sort could be devised to explain, if not the entire number, at least pieces of it. For a start, I would attempt a detailed study of past U.S. SSN deployments in order to get a more accurate picture of how the U.S. Navy is accustomed to utilizing these boats, data which I was unable to acquire during the writing of this paper as the Navy has not released it in compiled form.

Some broad conclusions can be drawn, however. Even assuming conservative (Navy official) deployment ratios, 45 SSNs is still in excess of the force required to execute the National Security Strategy. Given the current size and composition of the force, any future force can be constructed simply by selectively retaining a percentage of the existing boats; and this selectivity will allow the most modern and capable boats to be retained, producing an increase in the average capability of the SSN fleet. Furthermore, new construction need not be onerous; even with the scenarios I have devised, one unit per year NSSN construction need not begin until 2009, with 0.5 unit/year construction from 1998-2009. Further delays in beginning NSSN construction might be purchased at the expense of anticipating higher construction rates, temporarily, beginning after 2010.

The United States Navy is in a position to pick and choose. They can also choose the best, and choose to keep few enough SSNs to reduce the burden on the American defense budget.

* * *


1 William Perry (Secretary of Defense), Annual Report to the President and Congress 1995. Washington D.C: Dept. of Defense, 1995. p.184.
2 Ronald O'Rourke, Naval Force Structure Planning: Breaking Old Habits of Thought CRS issue brief #93-332F. Washington D.C: Congressional Research Service, 1993. p.1.
3 William Perry, Annual Report to the President and Congress. op. cit. p.2.
4 ibid. p. 3.
5 Les Aspin, The Bottom-Up Review. Washington D.C.:Department of Defense, 1993. p.7.
6 ibid. p.15.
7 ...From the Sea. Navy and Marine Corps White Paper. Washington D.C.: Department of the Navy, 1992. p.3.
8 ibid. p.8.
9 A.D. Baker III. The Naval Institute Guide to Combat Fleets of the World 1995 Annapolis: Naval Institute Press,1995. pp. 860-862.
10 From a discussion with the Weapons Crew of SSN 703 USS Boston, homeported at Groton CT. on April 21,195.
11 Nora Slatkin (Asst. Secretary of the Navy) Statement before the Subcommittee of National Security of the House Appropriations Committee on FY 1996 Submarine Modernization Plan, April 5, 1995. p.2.
12 William Perry. Annual Report tothe President and Congress. op. cit. p.189.
13 Norman Friedman. 'Submarines Adapt' in Proceedings of the U.S. Naval Institute November 1994. Annapolis: Naval Institute Press, 1994. p.72.
14 Horton, Edward. The Illustrated History of the Submarine. New York: Doubleday & Company, 1974. p. 56.
15 Jan Breemer. Soviet Submarines;Design, Development and Tactics. Surrey: Jane's Information Group, 1989. p.81, 'The Soviet 'anti-SLOC threat.' Breemer notes that although these concerns may have made sense by the 1960's, at that time it was generally realized that the Soviets did not possess the submarine forces capable of waging a U-boat style tonnage war against the NATO allies in the early 1950's.
16 Posen, Barry R. Inadvertent Escalation. Ithaca: Cornell University Press, 1991. pp.159-160.
17 Kuenne, Robert. The Attack Submarine: A Study in Strategy. New Haven: Yale University Press, 1965. p.6.
18 Nora Slatkin (Asst. Secretary of the Navy). Statement before the Subcommittee on Nat'l Security op. cit. Presentation materials.
19 Jane's Fighting Ships lists the onboard armament of the U.S. Nimitz-class carriers as 3 8-round Sea Sparrow SAM launchers, range 14.6km and 4 Phalanx CIWS missile defense gun systems, point defense only.
20 Lt. Christopher P. Carlson USNR. 'How Many SSN's Do We Need?' in Proceedings of the US Naval Institute, July 1993 issue, p.52.
21 Class Lecture notes, 17.482J General Purpose Forces (MIT) Professor Posen. May 8, 1995.
22 The SS-N-19 'Shipwreck' missile has a range of up to 300 nm. See Captain Richard Sharpe RN, ed. Jane's Fighting Ships 1993-1994. Surrey: Jane's Information Group, 1993. p. 520.
23 This is an extrapolation on my part, taken from a taciturn but positive answer to my question of whether or not the SSN practices with the SSBN fleet, during a visit to SSN 703, USS Boston on April 21, 1995.
24 Ticonderoga class cruisers and Arleigh Burke (DDG-51) destroyers carry dedicated ASW helos; others, such as the nuclear cruisers, carry ASROC and torpedoes. (Jane's; Modern Naval Combat)
25 A.D. Baker III. Combat Fleets of the World 1995. op. cit. pp.554,860,862.
26 John H. Dalton (Secretary of the Navy). Remarks delivered to Congressional breakfast seminar; March 28, 1995.
27 Harold Hemond. 'Why Not Design the Best?' in Proceeedings of the U.S. Naval Institute July 1993. Annapolis: Naval Institute Press, 1993. p.55.
28 Kostas Tsipis. Tactical and Strategic Antisubmarine Warfare. Cambridge: The MIT Press, 1974. p.27.
29 Nora Slatkin (Asst. Secretary of the Navy) op. cit. Transparencies.
30 In Jane's Fighting Ships 1993-94, it is noted that the Russians possessed 13 Akulas, and that those after the 'fifth or sixth hull' are considered 'improved.' Combat Fleets of the World puts the number, as of 1995, at 13 active boats, of which 7 or 8 would be 'improved.'
31 Jan Breemer. Soviet Submarines: Design, Development and Tactics. op. cit. pp. 174-177.
32 John Wilson Lewis and Xue Litai. China's Strategic Seapower. Stanford: Stanford University Press, 1994. p.224.
33 Jan Breemer. Soviet Submarines: Design, Development and Tactics. op. cit. p.164 (chart). 34 Breemer p.63 and Carlson,p.50.
35 RAdm Edward Sheafer (Director of Naval Intelligence). Testimony before the Sea Power, Strategic and Critical Materials subcommitttee of the House Armed Services Committee, February 5 1992, p.16.
36 'Iran building up navy, Perry is told.' The Boston Globe, Wednesday March 22 1995. p. 15, col. 1.
37 For information about Iranian naval buildup, see Lt. (jg) James Kraska, 'Gatekeepers of the Gulf' in Proceedings of the U.S. Naval Institute, March 1994.
38 This is a phrase I have picked up from U.S. Naval officers on the Internet; I speculate it refers to the Swedish-built 'Boghammar boat' which is a small, very high-speed cigarette type boat with limited endurance.
39 Les Aspin (Secretary of Defense). The Bottom Up Review: Forces for a New Era. op. cit. p.5
40 Lautenschläger, Karl. 'The Submarine in Naval Warfare,' in Miller, Steveen and Van Evera, Stephen eds. naval Strategy and National Security. Princeton: Princeton University Press, 1988. pp. 278-282.
41 A datum reported to me by Sharon Weiner (DACS) from conversation with the CO of SSN 702, USS Phoenix, during a visit to the boat at Norfolk Naval Base.
42 James George. The U.S. Navy in the 1990s. Annapolis: Naval Institute Press, 1992. p.74.
43 A.D. Baker III, Combat Fleets. op. cit. p.835.
44 ibid. pp. 864-865.
45 Jan Breemer. 'Where are the Submarines?' in Proceedings of the U.S. Naval Institute, January 1993. pp. 40,41.
46 Tom Stefanick. op. cit. frontispiece.
47 Ronald O'Rourke makes this point in Naval Forward Deployments and the Size of the Navy. CRS Brief 92-803F. Washington D.C: Congressional Research Service, 1992. p. CRS-13
48 Ronald O'Rourke, ibid. p. CRS-14.
49 A.D. Baker III, Combat Fleets. op. cit. p. 859.
50 Ronald O'Rourke, Naval Forward Deployments op cit p.CRS-19.
51 William Perry (Secretary of Defense). Annual Report 1995, op. cit. pp. 189-190.

Back to Part I

Log in or register to write something here or to contact authors.