Contact Us   |    Join   |    Donate


The need for submarines and submarine weapons in the U.S. Navy is highly sensitive to the missions the nation expects these submarines to undertake if called upon. In this paper are examined the missions, proven and unproven, which drive the need for submarines and their weapons.

The history of the underwater war of 1939-1945 is particularly relevant because it was the last time that submarines were in a major action. (The Falkland’s War saw too little submarine action to provide a good base for weapon usage.)

In 1939, the first U-boat commanders were directed by the German Naval High Command by message to: “Commence hostilities against Britain forthwith.” It is important to note that with regard to merchant shipping, the campaign was initially directed to be waged “in accordance with the revised issue of the Prize Regulations until such time as danger areas are declared.” The regulations were those of the London Protocol (1936) which provided that unescorted merchant ships could be sunk only after being stopped and searched and after measures had been taken to ensure the safety of the people aboard. As the war progressed, several honest errors were made, tankers became exceptions, and by May, 1940, German submarines no longer bothered with protocols.

In the pre-World War II u.s. Navy, submarine commanders had to sign a detailed statement indicating their agreeement to abide — in times of war by the protocols and other internationally accepted modes of behavior. But by the time Pearl Harbor was attacked, emotions had heated up and passions ran high. The first wartime command to U.S. submarines in the Pacific was: “Execute unrestricted (air and) submarine warfare against Japan.” The lesson is clear: weapons of war are not necessarily used for the purpose for which they were designed.

The lessons of war are many and depend to a large extent upon the viewpoint of the person drawing the conclusions. The foremost observation is that the most successful mission accomplished by submarines in World Wars I and II was the sinking of merchantmen in areas denied access to air and surface forces in spite of the fact that they were neither designed nor intended primarily as merchant raiders. Figure 1. illustrates this point.

View full article for table data

While there is no intention to downgrade the submarine’s ability to sink warships, their greatest success was by far against the merchant fleet. u.s. submariners generally will argue that the priority in the U.S. Navy was assigned early in the war to sinking warships. This emphasis was later shifted to merchantmen. Notwithstanding, there can be no question that the results against the merchantmen were far superior, about 10 to 1 in tonnage. Furthermore, whatever the reasons, u.s. carrier air forces sank about 15 percent more warships than did U.S. submarines. The principal conclusion is that submarines have a demonstrated capability to sink merchantmen far beyond any other capabilities they may have demonstrated or for which they were designed.

The second conclusion to be drawn for our purposes from World War II, the last war in which submarines in large numbers were used in anger, is that it takes many submarine torpedoes to conduct submarine warfare. While there are many extenuating and intricate explanations, the facts are that great numbers of torpedoes were used as shown in the following table:

View full article for table data

Thus, from about 4.5 to 11 to 1 is the range of ratios of the number of torpedoes launched in anger to the number of ships sunk.

The third major conclusion from the underwater action of World War II is that surface forces and air forces killed about the same number of enemy submarines while submarines killed by comparison many fewer.

The following table (calculated in 1958 and said to contain a few minor errors) shows the breakdown of enemy submarine sinkings by nationality of submarine sunk, and by the character of the attacking Allied Forces.

View full article for table data

Of submarines sunk by submarines, all enemy submarines but one were either surfaced or in the act of surfacing/diving when sunk. There was one case of a submarine (British) which sank an enemy submarine (U-boat) while both were completely submerged. Six Japanese submarines were sunk by U.S. submarines while the former were in the act of surfacing or diving; 19 more were sunk on the surface. The location of submarines sunk by submarines was generally in areas over which Allied forces did not have control. These included offshore enemy submarine training areas, enemy submarine training areas, enemy-air controlled lanes, etc.

The three conclusions I want to carry forward from World War II in summary are:

  1. Submarines did a highly effective job of killing merchantmen, and, to a much less extent men of war, mostly in areas denied access to other forces.
  1. It took in the order of 5-10 torpedoes, or more for every ship a submarine sank.
  1. Submarines did not demonstrate the capability of killing submerged submarines.

To what degree do these conclusions apply to Submarine forces of the world today?

There appears to be every reason to believe that conclusion 1. — capability against merchant ships — is probably true today and will remain true for the foreseeable future. With regard to torpedoes, the higher sophistication and capability of today’s MK 48 torpedoes should require fewer numbers of torpedoes per ship kill, perhaps 3 to 4 instead of 11, but there is no irrefutable way to determine such an estimate. Lastly, the third conclusion does not hold today. There is no question that today U.S. submarines have the capability to sink submerged submarines. Short of actually fighting a war in which submarine ASW was conducted in anger, there probably is little more the Navy could do to demonstrate this capability. Submarine ASW capability has been proved by analysis, by exercise and under relatively realistic conditions.

How ASW came to be a primary mission of submarines is worthy of description considering the fact that in World War II , of the almost 1,000 enemy submarines killed, a high percentage of them were killed either in port or at sea, caught on the surface usually in periods of low visibility, detected by the emerging radars of the time, and operating in a benign countermeasures environment.

It is no secret that internecine forces are always at play between the various tactical divisions within the u.s. Armed Forces. Those between the air, surface, and submarine forces in was  developed.

  1. The ballistic missile submarine (designated SSBN) was developed and deployed.
  1. Some of the special missions became less attractive in stark reality (e.g., sea-planes for ASW disappeared from the Navy).
  2. There were complicated command problems (e.g., SSRs were under the operational command of the surface forces and not the submarine forces.
  1. A real threat– the Soviet submarine force- became a rallying point for the Navy in Congress. Hence anti-submarine warfare became the best game in town.

All of the above developments, in combination, resulted in the decision in late 1960 and early 1961 to redesignate all submarines “counted” for force level purposes to be designated as SS or SSN, depending only on their propulsion plant. In addition, there were the SSBNs, and a few AGSSs (having little combat capability and not counted in force levels.) One of the principal arguments used to make the changes in designation was that all submarines now had an ASW capability and therefore, in view of the Soviet submarine threat, the primary mission of all submarine forces was anti-submarine warfare. The submariners had consolidated their position and raison d’etre, and had clearly identified a credible threat. Their hand was further strengthened by the decision to develop and deploy the SSBN. During this period of development and deployment, the submarine force still represented only 5 to 6 percent (growing to 8 to 11 percent) of the personnel in the Navy and was getting about 25 percent of the Navy procurement  and  R & D budget.

What is the general nature of the submarine threat?

There are about 800-900 submarines in commission world-wide, of which the submarine levels of major submarine nations are shown in the table, along with the number such nations had at the beginning of World War II.

View full article for table data

In 1939, the Soviets had over 200 subs from whose force very little was heard in the next six years, but a great deal has changed. The Soviet Navy is better trained and more aggressive. The world-wide objectives of the Soviet government are clearer. The USSR is a superpower.

How can these submarines threaten u.s. security? I think it is clear that submarines can sink merchantmen and the Soviet force could indeed pose a threat probably sufficient to make it very difficult for the 500 ship merchant fleet owned by the U.S. and whatever other ships could be brought into service from the aging reserve fleet and the “flags-of-convenience”  fleet.The  threat to our warships is existent, particularly if cruise-missiles are used, but the capability is far from demonstrated as is, for example, the threat to our warships from aircraft armed with air-to-surface missiles. Finally, the threat of attack to the U.S. itself from Soviet ballistic missile submarines is real enough but no decision or commitment has been made to systematically reduce this threat. Without some kind of world-wide, 24-hour localized surveillance by forces ready to launch weapons instantaneously, together with boost-and mid-phase intercept and terminal ballistic defense systems, there is little hope of reducing the threat of submarine ballistic missile attack on the U.S. by ASW alone to a point where damage to the U.S. could be seriously reduced .

Where  does   that  leave  us?

  1. S. submarines   can   sink   merchantmen. There  are  about  1,723  Soviet  merchantmen, about  600  auxiliary  naval  ships,  and  an additional  number  of  Soviet  large  fishing vessels.
  1. s. submarines may be able to deal with some degree of success with Soviet men of war; while the Soviets have the same potential.
  1. s. submarines have developed a highly sophisticated ASW capability.
  1. The s. needs weapons of appropriate quality and sufficient numbers.

Today the U.S. submarine force and its weapons are designed primarily for ASW. The capability against merchant and combatant ships is accepted as a by-product.

The Mk-48 is the best ASW weapon design to date and it has been continuously modernized. ADCAP will be an improvement aimed at dealing with the newer Soviet submarines. Both are “optimized” against the submarine; both may be used against surface ships, although their sophistication is not needed for that mission. The requirement for anti-submarine use drives the cost and makes it probably 2 to 4 times what a weapon designed for anti-surface ship use would cost.

There is then the question of the numbers of weapons! A short review of the Navy’s system of producing the so-called non-nuclear ordnance requirements (NNOR} is in order, for a better understanding. The NNOR system is a quota system. The target set is defined and then a subset is arbitrarily allocated to each U.S. force. For example, the 1,200 some Soviet combatant ships and auxiliaries are arbitrarily allocated to U.S. forces for attack and sinking; so many to subs, so many to aircraft (with bombs), so many to aircraft (with missiles), so many to cruisers, so many to destroyers, etc. Then, theoretical reliability figures are applied and the number, say, of MK-48’s is calculated accordingly. The false target problem is essentially ignored.

If that system had been used in the late thirties, U.S. submarines would have had available for World War II only 2,000 to 3,000 torpedoes at most and not the 15,000 it actually used. This leads to the conclusion that not only are U.S. present submarine weapons misfitted to the whole target set in a systems sense, but also that the method used to calculate stockpile requirements is woefully inadequate from a readiness point of view, albeit practical from a budgetary and programmatic  viewpoint.

A comprehensive submarine weapon study is needed; however some simple arithmetic can bound the requirements. Table V shows approximations as to torpedo requirements calculated for two assumptions regarding the percentage of enemy ships that U.S. subs may have to attack. Again false submarine targets severely impact the requirements.

Thus in 1984, as we look at the next 20 years, there appears to be a clear path for improvement in the strategy for stockpiling of submarine weapons. Conceptually, a family of submarine weapons is indicated.

First and foremost, there is a need for a weapon –a torpedo would do– specifically designed to sink surface ships, particularly merchantmen. It seems that such a weapon could be produced in the quantities needed at a fraction of the cost of ADCAP. A practical goal is three to five times the number of surface ships which submarines could be expected to kill. · For starters, if one assumed that sinking one-half of the Soviet merchant and combat force is a reasonable planning goal, we would need a minimum of about 6, 000 such weapons; the upper bound of such an inventory would be about 10,000 to 15,000 which would take care of all Soviet merchant and combatant fleets using the five-to-one ratio.

Second, the MK-48 and ADCAP in the numbers planned could be reserved for use against submarines and, to a lesser extent, warships. There are about 600 to 700 such ships in the Soviet Navy. A moderate number of Harpoon/Cruise Missiles could assist in the warship attack role.

Third, a simple weapon could be fielded for a submarine to protect itself from ASW fixed-wing aircraft and helicopters. Several tests of this type of weapon have been successfully conducted since World War II and there is no technical impediment to the deployment of a simple, effective and inexpensive weapon system for this purpose.

Fourth, a modern mining capability would round off the weapon arsenal for u.s. submarines. Enough attention has not been paid to this inexpensive unique and effective method of conducting naval warfare.

Additional consideration should be given to (l)a new mission and (2)a special heretofore unavailable option for submarine weaponry.

The new mission would involve submarine participation in the outer air battle, one of the difficult problems associated with U.S. surface systems. The geometry associated with detection and intercept of Soviet Backfire/Blackjack bombers armed with air-to-surface missiles, on strike missions against U.S. surface ships, is such that U.s. warning time and reach of defensive weapons is inadequate. A system should be thoroughly examined whereby U.S. sub1118rines in the forward areas, on command, would act as launch platformsfor surface-to-air missiles to predesignated spatial windows for subsequent control by some external system (satellites, high flying aircraft) to intercept Soviet bombers long before reaching their launch positions.

Lastly, there is a new need, in the submarine family of weapons, for a disabling weapon. The Falkland/Maldive action and the resultant sinking of the Argentine cruiser Belgrano, with the subsequent loss of about 500 personnel, has highlighted at least the political need in special circumstances of a way to disable a ship, put it out of action and ye~ not result in needless loss of     life.For  other than humane reasons, a disabling attack would be of great value. The possible environmental damage to friendly shores and fisheries (e.g., in the Mediterranean or Persian Gulf) caused by the sinking of supertankers mignt far outweigh the possible military value of such sinkings. Furthermore, the option to disable does not close the option to sink.

These six weapons, anti-surface, Mk 48/ADCAP, submarine self-defense against aircraft, mines, outer-battle launch-and-forget and a disabling weapon, developed and deployed in a systematic and balanced way would ensure that a submarine force is ready for modern warfare. The greatest deficiency moreover is the anti merchant ship weapon.


Naval Submarine League

© 2022 Naval Submarine League