What would you pick? Here is what one of the world's most sought after naval experts came up with...

There have been three great submarine campaigns in history, and one prolonged duel. The First and Second Battles of the Atlantic pitted German U-boats against the escorts and aircraft of the United Kingdom and the United States. The Germans very nearly won World War I with the first campaign, and badly drained Allied resources in the second. In the third great campaign, the submarines of the US Navy destroyed virtually the entire commercial fleet of Japan, bringing the Japanese economy to its knees. US subs also devastated the Imperial Japanese Navy, sinking several of Tokyo’s most important capital ships.

But the period most evocative of our modern sense of submarine warfare was surely the forty year duel between the submarines of the USSR and the boats of the various NATO navies. Over the course of the Cold War, the strategic nature of the submarine changed; it moved from being a cheap, effective killer of capital ships to a capital ship in its own right. This was especially the case with the boomers, submarines that carried enough nuclear weapons to kill millions in a few minutes.

As with previous “5 Greatest” lists, the answers depend on the parameters; different sets of metrics will generate different lists. Our metrics concentrate on the strategic utility of specific submarine classes, rather than solely on their technical capabilities.

· Was the submarine a cost-effective solution to a national strategic problem?

· Did the submarine compare favorably with its contemporaries?

· Was the submarine’s design innovative?

And with that, the five best submarines of all time:

U-31:

The eleven boats of the U-31 class were constructed between 1912 and 1915. They operated in both of the periods of heavy action for German U-boats, early in the war before the suspension of unrestricted warfare, and again in 1917 when Germany decided to go for broke and cut the British Empire off at the knees. Four of these eleven boats (U-35, U-39, U-38, and U-34) were the four top killers of World War I; indeed, they were four of the five top submarines of all time in terms of tonnage sunk (the Type VII boat U-48 sneaks in at number 3). U-35, the top killer, sank 224 ships amounting to over half a million tons.

The U-31 boats were evolutionary, rather than revolutionary; they represented the latest in German submarine technology for the time, but did not differ dramatically from their immediate predecessors or successors. These boats had good range, a deck gun for destroying small shipping, and faster speeds surfaced than submerged. These characteristics allowed the U-31 class and their peers to wreak havoc while avoiding faster, more powerful surface units. They did offer a secure, stealthy platform for carrying out a campaign that nearly forced Great Britain from the war. Only the entry of the United States, combined with the development of innovative convoy tactics by the Royal Navy, would stifle the submarine offensive. Three of the eleven boats survived the war, and were eventually surrendered to the Allies.

Balao:

The potential for a submarine campaign against the Japanese Empire was clear from early in the war. Japanese industry depended for survival on access to the natural resources of Southeast Asia. Separating Japan from those resources could win the war. However, the pre-war USN submarine arm was relatively small, and operated with poor doctrine and bad torpedoes. Boats built during the war, including primarily the Gato and Balao class, would eventually destroy virtually the entire Japanese merchant marine.

The Balao class represented very nearly the zenith of the pre-streamline submarine type. War in the Pacific demanded longer ranges and more habitability than the relatively snug Atlantic. Like their predecessors the Gato, the Balaos were less maneuverable than the German Type VII subs, but they made up for this in strength of hull and quality of construction. Compared with the Type VII, the Balaos had longer range, a larger gun, more torpedo tubes, and a higher speed. Of course, the Balaos operated in a much different environment, and against an opponent less skilled in anti-submarine warfare. The greatest victory of a Balao was the sinking of the 58000 ton HIJMS Shinano by Archerfish.

Eleven of 120 boats were lost, two in post-war accidents. After the war Balao class subs were transferred to several friendly navies, and continued to serve for decades. One, the former USS Tusk, remains in partial commission in Taiwan as Hai Pao.

Type XXI

In some ways akin to the Me 262, the Type XXI was a potentially war-winning weapon that arrived too late to have serious effect. The Type XXI was the first mass produced, ocean-going streamlined or “true” submarine, capable of better performance submerged than on the surface. It gave up its deck gun in return for speed and stealth, and set the terms of design for generations of submarines.

Allied anti-submarine efforts focused on identifying boats on the surface (usually in transit to their patrol areas) then vectoring killers (including ships and aircraft) to those areas. In 1944 the Allies began developing techniques for fighting “schnorkel” U-boats that did not need to surface, but remained unprepared for combat against a submarine that could move at 20 knots submerged.

In effect, the Type XXI had the stealth to avoid detection prior to an attack, and the speed to escape afterward. Germany completed 118 of these boats, but because of a variety of industrial problems could only put four into service, none of which sank an enemy ship. All of the Allies seized surviving examples of the Type XXI, using them both as models for their own designs and in order to develop more advanced anti-submarine technologies and techniques. For example, the Type XXI was the model for the Soviet “Whiskey” class, and eventually for a large flotilla of Chinese submarines.

George Washington:

We take for granted the most common form of today’s nuclear deterrent; a nuclear submarine, bristling with missiles, capable of destroying a dozen cities a continent away. These submarines provide the most secure leg of the deterrent triad, as no foe could reasonably expect to destroy the entire submarine fleet before the missiles fly.

The secure submarine deterrent began in 1960, with the USS George Washington. An enlarged version of the Skipjack class nuclear attack sub, George Washington’s design incorporated space for sixteen Polaris ballistic missiles. When the Polaris became operational, USS George Washington had the capability from striking targets up to 1000 miles distant with 600 KT warheads. The boats would eventually upgrade to the Polaris A3, with three warheads and a 2500 mile range. Slow relative to attack subs but extremely quiet, the George Washington class pioneered the “go away and hide” form of nuclear deterrence that is still practiced by five of the world’s nine nuclear powers.

And until 1967, the George Washington and her sisters were the only modern boomers. Their clunky Soviet counterparts carried only three missiles each, and usually had to surface in order to fire. This made them of limited deterrent value. But soon, virtually every nuclear power copied the George Washington class. The first “Yankee” class SSBN entered service in 1967, the first Resolution boat in 1968, and the first of the French Redoutables in 1971. China would eventually follow suit, although the PLAN’s first genuinely modern SSBNs have only entered service recently. The Indian Navy’s INS Arihant will likely enter service in the next year or so.

The five boats of the George Washington class conducted deterrent patrols until 1982, when the SALT II Treaty forced their retirement. Three of the five (including George Washington) continued in service as nuclear attack submarines for several more years.

Los Angeles:

Immortalized in the Tom Clancy novels Hunt for Red October and Red Storm Rising, the U.S. Los Angeles class is the longest production line of nuclear submarines in history, constituting sixty-two boats and first entering service in 1976. Forty-one subs remain in commission today, continuing to form the backbone of the USN’s submarine fleet.

The Los Angeles (or 688) class are outstanding examples of Cold War submarines, equally capable of conducting anti-surface or anti-submarine warfare. In wartime, they would have been used to penetrate Soviet base areas, where Russian boomers were protected by rings of subs, surface ships, and aircraft, and to protect American carrier battle groups.

In 1991, two Los Angeles class attack boats launched the first ever salvo of cruise missiles against land targets, ushering in an entirely new vision of how submarines could impact warfare. While cruise missile armed submarines had long been part of the Cold War duel between the United States and the Soviet Union, most attention focused either on nuclear delivery or anti-ship attacks. Submarine launched Tomahawks gave the United States a new means for kicking in the doors of anti-access/area denial systems. The concept has proven so successful that four Ohio class boomers were refitted as cruise missile submarines, with the USS Florida delivering the initial strikes of the Libya intervention.