The British Submarine Campaign of World War II

It is inevitable that the great deeds of British submariners in the Second World War would be overlooked by most. Their fight was not as critical as that of the German u-boats in the Battle of the Atlantic nor as single-handedly successful as the American submarine campaign in the Pacific, however, it would be wrong to ignore it. The submarines of the Royal Navy played, if not a decisive factor, certainly an extremely significant one in the ultimate victory over the Axis powers, particularly Germany and Italy. The British are mostly known, because of the world wars, as being on the receiving end of submarine warfare rather than the ones waging it and, indeed, Britain would lead the way in anti-submarine warfare particularly during World War II. Nonetheless, while the convoy escorts braving the perilous North Atlantic crossing or the warships chasing down German or Italian battleships got most of the attention, the submarines of the King-Emperor went about their work silently severing the vital arteries that kept the Axis powers functioning and their armies on the advance.

HMS Totem

Great Britain began the war with a fleet of 57 submarines, the exact same number as the Germans. The Royal Navy produced quite a large number of different classes of boats but three would be most prominent; the S, T, and U-class boats of which the most famous is probably the T-class. Like the Italians, who had a very large submarine force, the British opted for reliability rather than innovation. For instance, like the Italians, they stuck to the old-fashioned impact fuse for their torpedoes rather than the more sophisticated magnetic fuses used by the Germans and Americans. This made them less effective but, unlike both Germany and America, Britain did not have to go through a period of having unreliable or totally faulty weapons while the bugs were worked out of this new technology. Rather, the British compensated for the weaker destructive power of the impact fuses (in which the brunt of the explosion is focused away from the target) by having boats that packed a larger punch than those of any other navy. British T-class submarines were built to fire an astonishing 10 torpedoes at a time which, British naval engineers reasoned, would more than make up for the drawbacks of their fuses as well as the less advanced targeting systems of British boats. If ten torpedoes are fired at a single target, one or more will almost have to hit it.

When war broke out in 1939, British boats were deployed to Heligoland to patrol the waters off the southwest coast of Norway for German ships and u-boats. Unfortunately, this proved very dangerous even without the Germans as British submarines sometimes fired on each other, mistaking their submarines for German u-boats. Likewise, even when in their designating hunting areas, British submarines were sometimes attacked by the RAF who mistook them for German u-boats. However, the British subs did finally score their first victories with successful attacks by two S-boats. HMS Sturgeon sank a German ship in November and HMS Salmon sank a German u-boat two weeks later. The British submarines would gain a high reputation for their ability to sink enemy submarines at a time when surface ships were still assumed to be their primary targets. The Royal Navy proved that the best weapon to use against a submarine is another submarine and that fact remains true to this day. By the time the war was over, British submarines would account for the loss of 39 Axis subs.

Admiral Horton, 1940

In January of 1940 the Brits would step up their game with the appointment of Vice Admiral Max Horton to command the Royal Navy submarine force. He was a living legend in the submarine community for his fantastic record of success in the Baltic as a submarine commander in World War I. After Britain sustained her first losses to enemy action, it was Horton who ordered British boats to stay out of the shallower waters where German underwater detection gear was less effective. Horton planned to use submarine planted mines to cut off the supply of raw materials coming out of Scandinavia to Germany, which would likely force Germany to invade Norway. As it happened, the Germans did invade Norway though not for that reason. Unfortunately, due to weather conditions and bureaucratic slowness, the Germans were able to slip past the British boats and land their forces before the Royal Navy could react. Nonetheless, the British subs did get a few powerful blows in. HMS Truant sunk the German cruiser Karlsruhe and HMS Sunfish sank a 7,000-ton freighter followed by another before the day was out.

Unfortunately, even with 17 boats in the vicinity, the big game proved elusive. The prized German warships Gneisenau, Hipper and Scharnhorst all escaped attacked due to poor visibility and radio direction-finding by German shore installations which were able to direct their ships around areas where British submarines were on the prowl. This was a problem that would come up again later. There were other minor successes but the fact remains that the British submarine force had failed to stop the German invasion and the Royal Navy had been forced to rely only on the submarine force because of the effectiveness of the Luftwaffe in keeping the British surface fleet away. Likewise, operations off the North Sea coast during the German invasion of France and the Low Countries proved to be of little effect. Concentrating boats in these confined spaces had proved to be a mistake, due to the effectiveness of shore installations in homing in on their radio transmissions, the risk of “friendly fire” and the constant daylight in northern areas.

HMS Phoenix

Fortunately for Great Britain, much more success was to be found in the waters of the Mediterranean where British submarines would have their biggest impact on the war. The largest threat, obviously, was the powerful Italian navy and the extensive coverage over the Mediterranean by the Italian air force. However, due to the shortage of fuel and their industrial inability to keep up with any significant rate of attrition, the Italian surface navy would be forced to remain on the defensive. The first British submarine success in the Mediterranean was, due to confusion over their status, the sinking of a French sloop. While screening a convoy, the submarine HMS Phoenix spotted the main Italian fleet, leading to a fairly significant engagement, but the Phoenix was then sunk by an Italian torpedo boat on July 16, 1940. On the final day of the month, HMS Oswald was sunk by an Italian destroyer off the coast of Messina. As the Germans had done in the North Sea, Italian shore installations used radio direction-finding to locate the British submarine and the Italian destroyers then moved in for the kill.

Morale fell as British submarine losses continued and though successes did increase when the government in London authorized the use of unrestricted submarine warfare, the latter half of 1940 was fairly disastrous for the Royal Navy boats. While sinking less than 1% of Italian shipping to North Africa, Britain had lost nine submarines, five at the hands of the Italian navy and the rest to air attack or mines. At one point, Britain was reduced to only five operational boats in the Mediterranean. Clearly, something had to be done. Italian shipping losses had been extremely light in 1940, warships were not engaged and overall Italian superiority in the central Mediterranean had been maintained. It was a gloomy time as the British came to grips with the fact that, despite what Allied propaganda had told them, their enemy was a formidable one. However, the British did what they have traditionally done; learned from their mistakes and adapted.

HMS Upright

As with the Germans (or the Japanese for that matter), Italian underwater detection gear was not good. The British knew this and so finally came to appreciate that, other than aircraft, the primary way their boats were being located was by radio direction-finding. The British responded by ordering their subs to maintain radio silence unless communication was absolutely necessary. The British also ultimately adopted the practice of keeping their boats submerged throughout the daylight hours if at all possible, only surfacing at night. This reduced their mobility of course but also made them much less likely to be detected by lookouts on ship or shore or by patrolling Italian aircraft. The Admiralty also sent many more submarines to Malta such as 10 new U-class boats in early 1941. With a greater respect for their enemy, more care given to stealth and increased use of mines, British successes began to pick up. In February of 1941 HMS Upright attacked and sank the Italian cruiser Armando Diaz in a surface attack at night, the biggest victory British submarines had yet had in the Mediterranean.

In March, HMS Rorqual laid a minefield, sent two freighters to the bottom and then sank the Italian submarine Capponi. The same month, another British boat, the P31, made a successful attack on a large freighter using Asdic (sonar) alone, earning the commander the DSO. The following month also saw the beginning of a string of victories for the man who would be the most successful British submarine commander of World War II, Lt. Comm. Malcolm D. Wanklyn of HMS Upholder. He sank a freighter in April off Tunisia and two more on May 1, beginning what would be a very successful career, albeit a short one. Sadly, Wanklyn was killed in action in 1942 by the Italian navy but by that time had managed to sink 21 Axis vessels, earning the Victoria Cross. Because of men like him, things were turning around for the British war under the waves. In the first half of 1941 they managed to sink about 130,000 tons of Axis shipping while losing only two submarines, both to Italian minefields. Still, the rate of success was slow at less than two ships a month and of the shipping interdicted by the Allies, including the movement of Rommel’s Afrika Korps to Libya, less than 5% was lost to British submarines.

HMS Upholder

However, the British were steadily improving and were aided by two significant events; the invasion of the Soviet Union, which meant the redeployment of enemy air forces and the breaking of Axis codes which allowed the British to have up to date information on Italian naval movements. The British also very cleverly took care to move aircraft into the area of Italian convoys before the submarines arrived to make their attack so that the Axis high command would assume the RAF had spotted their ships and not catch on to the fact that their codes had been broken. This allowed for more British submarines successes going forward. In September of 1941 the boats at Malta were organized into the Tenth Submarine Flotilla and the “Fighting Tenth” would prove the most successful British submarine force of the war, though also the one with the highest casualty rate.

Having inside information on when and wear Italian supply convoys would be sailing, the British were able to post their submarines in picket lines in front of the enemy. In so doing, the British boats began to really bite into the Axis war effort, sinking four Italian troopships in a few weeks and badly damaging the new Italian battleship Vittoria Veneto which was attacked by HMS Urge and put out of action for over three months. In the second half of 1941 the British lost six submarines but received 13 new boats and in that time managed to take a significant toll on Axis shipping which was critical to the North African war effort. In the desert, logistics were paramount and when the supplies flowed, Rommel advanced; when they did not, the Italo-German forces fell back. The losses were serious enough to compel the Germans to dispatch some of their own u-boats to the Mediterranean, adding a new and dangerous foe for the British to deal with, proven when the U-81 managed to sink the only British aircraft carrier in the Mediterranean, HMS Ark Royal, in November. Moreover, German and Italian air attacks on Malta proved to be devastating, eventually wiping out the RAF defenders, forcing the withdrawal of many ships and damaging three submarines.

HMS Unbeaten

Nonetheless, the British boats continued to put up a terrific fight with HMS Upholder sinking the Italian submarine St Bon in January of 1942 and HMS Unbeaten sinking the German submarine U-374 not long after. In March the Upholder sent another Italian submarine, the Tricheco, to the bottom off Brindisi. However, the Germans had developed better detection gear and shared this with the Italians to great effect. The Italian torpedo boat Circe took out two British submarines using the new gear. The Italians also made ever greater use of minefields and this, combined with the sinking of the British minesweepers, ultimately made Malta untenable as a naval base. The island was ripe for the picking, however, it was saved by German Field Marshal Rommel who convinced the high command to call off the invasion in favor of his attack into Egypt. At one point only 12 British boats were on hand in the area and the Royal Navy was more stretched than ever with the Empire of Japan now menacing the British Empire in the Far East. Many of the boats previously stationed in Malta had been transferred from Asia, which was now also under attack.

Dogged determination proved effective though and despite the reduction in numbers in April of 1942, British submarines sank 117,000 tons of Axis shipping along with the Italian cruiser Bande Nere (sunk by HMS Urge), a destroyer and six Axis submarines. It amounted to only 6% of the materials being sent to Rommel in North Africa but, due to the withdrawal from Malta, was significantly more than what the RAF had managed to intercept. British submarines were also being used to carry cargo to keep Malta alive as Italian naval forces prevented much of the surface convoys from landing their supplies. To fight back against this, British submarines were dispatched to prowl outside the main anchorages of the Italian fleet, to attack when possible but also to warn the high command of when they were moving out. The result was a fierce fight for control of the Central Mediterranean with wins and losses for both sides. However, the need for Axis air power on the Russian front gave the British some breathing room and soon more and more Royal Navy subs were posted to the Mediterranean with new flotillas organized in Gibraltar and Beirut.

HMS Urge

The British war effort was also aided by the fact that the increasingly critical fuel shortages meant that the main Italian battlefield was forced to stay in port most of the time and this, combined with the determination of British air and naval forces, meant that Malta was able to be built back up and more Axis shipping to North Africa was sunk. In October of 1942, even while preparing for the invasion of French North Africa, British submarines still sank 12 enemy ships and one destroyer. When the Axis powers began moving men and supplies into Tunsia to counter the arrival of the Americans, British submarines accounted for 16 ships lost while the RAF took out even more. Their actions were making it ever more difficult for the Axis forces in North Africa to be maintained much less take offensive action. By 1943 the Gibraltar flotilla moved to Algeria, Allied air power dominated the Mediterranean and the Axis shipping lanes were devastated with British submarines accounting for 33 Axis ships. In early 1943 the subs destroyed more ships at sea than any other force, surpassed only by Allied aircraft whose successes included ships in port.

Axis power was receding in the Mediterranean and the British boats were at the forefront of the naval victory thanks to men like Comm. J. W. Linton of HMS Turbulent who was killed in action after sinking 90,000 tons of enemy shipping and an Italian destroyer. He was posthumously awarded the Victoria Cross. Comm. George Hunt of HMS Ultor sank more Axis ships than any other British submarine commander at 30 for which he earned the DSO with bar twice. Comm. Ben Bryant was similarly decorated for sinking over 20 Axis vessels as well as numerous warships. With the capture of Sicily by the Allies, the naval war was practically over but, while outpaced by the air forces, Allied submarines, mostly British, accounted for roughly half of all Axis naval losses in the Mediterranean.

HMS Tally-ho

Of course, though less extensive, the Royal Navy submarine force also saw plenty of action in the Far East though they were only able to really establish themselves from August 1943 onward. Based out of Ceylon, their primary area of operations was the strategic Malacca Straits. In November HMS Tally-ho sank a small tanker, the first victory of British subs in Asian waters, but a more significant success was the sinking of the Japanese submarine I-34 by HMS Taurus. By 1944 the Royal Navy was getting back up to strength in East Asia and more submarines were dispatched as well. In January of 1944 HMS Tally-ho, commanded expertly by Lt. Comm. L.W.A. Bennington, sank the Japanese cruiser Kuma and, despite operating in only 15 fathoms of water, managed to escape the counter-attack of its escorting destroyer. Toward the end of the war, targets became scarcer and the Japanese were forced to resort to the use of primitive sailing ships not worth the expenditure of a torpedo. So, British boats, like their American counterparts, began making greater use of their deck gun.

East Asian operations were not as extensive but could still be intense. Lt. Comm. Anthony Collet of HMS Tactician saved a downed American pilot from the USS Saratoga despite being under enemy fire from shore batteries on Sabang and with a Japanese torpedo boat bearing down on them. For this act of heroism, Commander Collet was awarded the Legion of Merit from the United States. More British submarines were dispatched to the region and two new flotillas were organized. Their impact was not negligible and by late October 1944 the British subs had sunk 40,000 tons of merchant shipping, almost 100 small craft as well as a cruiser, three submarines and six smaller warships of the Imperial Japanese Navy. Not too bad. The smaller British subs were also able to operate in areas such as the Java Sea which were too shallow for the larger American boats. By March of 1945 all Japanese shipping in the Malacca Straits area had been virtually eliminated.

HMS Trenchant

In the build-up to the planned Allied assault on the Japanese home islands, British submarines at least 150 small craft but still managed to find some major enemy warships to target too. On June 8, 1945 Comm. A.R. Hezlet of HMS Trenchant spotted the Japanese cruiser Ashigara and fired a spread of eight torpedoes at 4,800 yards. Five hit home and the Ashigara went to the bottom. Perhaps the last really significant victory for the British was the attack on the Japanese heavy cruiser Takao at Singapore by the British mini-sub (XE-craft) XE-3 which earned her commander, Lt. Ian Edward Fraser, the Victoria Cross. The British submarines in East Asia performed very well and took a considerable toll on Japanese shipping while losing only three of their own boats in the process. They had also closed the Malacca Straits to Japanese shipping, choking off the supplies going to the Japanese forces confronting the British in Burma.

Overall, the British submarine force made a significant contribution to the defeat of Germany, Italy and Japan. Early on, they suffered some serious losses and learned some hard lessons against the Germans in the North Sea and the Italians in the Mediterranean. However, they adapted and came roaring back, taking a considerable toll on Axis warships and plaguing the supply lines keeping Rommel and his Italo-German forces in the field in North Africa. One of, if not the most decisive factor in the successful British defense of Egypt was Rommel’s lack of sufficient fuel and supplies and the British submarine force played a major part in that. Once the Mediterranean was secure, Britain was able to focus on East Asia where not much had been left by the American submarine campaign (the most successful in history) and yet, there too, the British boats played a significant part in disrupting the Japanese lines of supply and taking out several major enemy warships. The Royal Navy impact on the surface might have been more significant, and they may not get as much attention as some others but the British submarine force earned a record in battle during World War II that they can be proud of, contributing to the tradition that would carry Britain forward to the present day.

The Italian Submarine Campaign of World War II

As detailed previously on these pages (see here), none of the military forces of the major participant powers in World War II have been as unjustly maligned as those of the Kingdom of Italy. Italian defeats have been exaggerated and Italian successes often downplayed or ignored entirely. Because of this, the details of the Italian submarine campaign will no doubt come as a surprise to a great many people. However, the Regia Marina (Italian Royal Navy) entered the war with the largest submarine fleet in the world by tonnage and while most tend to think of the “Battle of the Atlantic” as solely a fight between German U-boat “wolf packs” and Allied convoys, the Italians participated as well, in fact, at one point there were more Italian submarines operating in the Atlantic than German ones. Italian boats also saw extensive service in the Mediterranean (naturally) and the Indian Ocean as well as undertaking operations to East Asian waters and the South Atlantic; areas beyond the range of the smaller, typical Type-VIIC German U-boats. Finally, Italian submarines did a great deal of damage, despite facing many difficulties, against the Allies.

The Smeraldo

When the Kingdom of Italy entered World War II with the declarations of war against Britain and France in June of 1940 the Regia Marina possessed 84 operational submarines under the overall command of Admiral Mario Falangola, succeeded at the end of the following year by Admiral Antonio Legnani. At the outset, their failures outnumbered their successes, which is not too surprising as, aside from some secretive operations in support of Franco in the Spanish Civil War, they had never been tested and both men and boats had bugs that needed working out. However, they had a spirit and determination that would prove formidable. The Smeraldo, for example, a Sirena-class boat of the short to medium range 600 series made the first torpedo attack on British shipping by an Italian submarine but the heavy seas caused the torpedo to miss. However, this same boat later endured the most intense anti-submarine warfare attack of any boat in history with British ships dropping 200 depth charges on her, and she still survived (ultimately this boat was sunk by running into a British mine some time later).

Capt. Enzo Grossi decorated by Adm. Doenitz

After the conquest of France and the establishment of German naval bases on the French west coast, Italian submarines were invited to participate in the campaign to strangle the British Isles. This, of course, meant a dangerous passage through the Straits of Gibraltar under the very noses of the British Royal Navy. Many German U-boats were lost in the straits but, though few are aware of it, no Italian submarine was ever sunk slipping through these dangerous waters. The Italians established themselves at Bordeaux under the name BETASOM (Beta [Bordeaux] Som [Sommergibili]) with 27 submarines in early 1941. Originally, the idea was the German and Italian submarines would work together in coordinated attacks against Allied shipping, however, this soon proved to be more troublesome than effective and few seem to understand why. Ultimately the cause was a difference in training and how German and Italian boats operated as well as the Germans not being what we would call “team players”.

Fairly quickly in the war, German submarines developed a preferred tactic of attacking on the surface at night, submerging to escape counterattack. Italian submarines, however, usually made underwater attacks during the daytime. This was one of the differences that made cooperation difficult. Probably the most significant, however, was the unwillingness of the Germans to place a German communications officer on Italian submarines, though they held overall command of joint-operations. The result of this was that an Italian submarine making contact with the enemy would have to signal Bordeaux which would then have to send the message to Paris to the German naval command which would then relay the message out to the German submarines in the area. Needless to say, this meant that by the time the Germans were told of an enemy convoy, it was too late for them to do anything about it.

Capt. Primo Longobardo

There was also an unwillingness on the part of the Germans to train the Italians to fit in with their preferred way of doing things and what training they did provide was inadequate, expecting the Italians to learn in only two months what it had taken the Germans years to develop and become proficient at. There is evidence that when Italian submarine captains were allowed to train with the Germans, the results were obvious. One such officer was Commander Primo Longobardo, one of the few to train with the Germans, and he proved one of the most successful Italian submarine commanders of the war. As captain of the submarine Torelli he once sank four Allied ships on a single patrol and ultimately accounted for 42,000 tons of Allied shipping sunk. In any event, when coordinated training was finally agreed to, joint operations had already been canceled and each submarine force operated on their own with the Italians mostly hunting in waters around the Azores and some boats dispatched for the South Atlantic, such as in the Brazilian shipping lanes, which they were able to reach more easily because of their greater range.

A lack of cooperation was also evident in the reluctance of the Germans to share their torpedo technology with the Italians. The Germans tried many innovations with their torpedoes, causing some problems as certain designs didn’t work but ultimately resulting in a more effective weapon. The Italians, on the other hand, simply stuck to their older but more reliable model which was not as effective and the Germans would not share their magnetic trigger technology with Italy until it was too late to be of best use. It is for this reason that Italian submarines frequently engaged in surface action as quite often they would make a successful underwater attack using their torpedoes but the target would be badly damaged but not sunk at which point the Italian submarine would surface and finish off the enemy with their deck gun. Italian sub crews also became, out of necessity, quite adept anti-aircraft gunners and this came about due to the nature of their boats.

A submarine on the surface is vulnerable and aircraft are a particularly dangerous enemy. They can be upon you very quickly and do immense damage, making it a life or death matter for a submarine to be able to submerge as fast as possible. As Italian submarines tended to be larger than their average German counterpart, this meant that they were slower to dive. A typical German submarine could submerge in about 20 seconds, whereas the average Italian submarine took between 60 and 120 seconds to get below the waves. One result of this was that, by the time an enemy aircraft was spotted, it was often better to take your chances shooting it out on the surface than be shot full of holes while trying to dive. It was not an enviable situation but it did make Italian AA fire more effective than in other navies. In fact, it was an Italian submarine, which had been shifted to the Germans after 1943 and then to the Japanese after the German surrender, which fired the last shots of World War II, using her AA battery against American bombers while in port in Japan.

Victory for the Leonardo DaVinci

In spite of their boats having their limitations, torpedoes that were not the best and a less than fully cooperative ally, Italian submarines still did a great deal of damage thanks to having some extremely skilled commanders. None was more famous than Gianfranco Gazzana-Priaroggia, captain of the Leonardo DaVinci, the most successful Italian submarine of the war. Nicknamed “Ursus atlanticus”, Gazzana-Priaroggia would ultimately sink over 90,000 tons of Allied shipping, his biggest score being the massive British troopship the Empress of Canada. He was even set to lead a special forces submarine attack on New York harbor but this was postponed and ultimately never carried out due to the 1943 armistice. Earlier that year, Gazzana-Priaroggia was sadly killed in action but was posthumously awarded both the Gold Medal for Military Valor by the King of Italy and the Knights Iron Cross by the Germans for his achievements. By most accounts (there is some dispute as the U.S. ‘updated’ their stats several times after the war) Gazzana-Priaroggia was the most successful non-German submarine commander of all time.

Todaro, the humane hunter

It is also worth noting, given that the Allies later justified their use of unrestricted submarine warfare by retroactively pointing to its use by Italian subs in the Spanish Civil War, that Italian submarines also had a reputation for gallantry and compassion. Every major participant of the war that made extensive use of submarines; the Germans, Americans, Japanese and British, were guilty of sometimes committing atrocities, invariably killing survivors of sunken ships. Japan had by far the most, the British and Americans extremely few and the Germans, well, given the details of the “Laconia Incident”, it is hard for anyone to blame them. However, the Italians were never accused of such cruelty and, indeed, came away from the war with a reputation for actually showing some basic humanity when it was not required. The most famous example of this was Captain Salvatore Bruno Todaro of the Commandante Cappellini which went above and beyond to rescue survivors of sunken ships and put them safely ashore on the Azores. At the same time, Todaro and his boat had multiple victories to their credit and were among the most successful of the Italian submarine fleet. When all was said and done, the Italian submarines sank over a hundred Allied ships in the Atlantic.

However, the Mediterranean Sea was, of course, always supposed to be the primary area of operations for all units of the Regia Marina and it was an enclosed sea of hazards with major British naval installations at Gibraltar, Malta, Alexandria and Cyprus. Italian submarine commanders pulled off some extremely daring victories against the British in these waters and aside from merchant shipping also took a heavy toll on Royal Navy warships. Notable successes include the cruisers HMS Bonaventure, HMS Calypso and HMS Coventry which were all sunk by Italian submarines in 1940-41. However, Italian industry could not produce new boats fast enough and the Allied breaking of Axis codes was also a huge blow to the submarine campaign. Nonetheless, Italian submarines in the Mediterranean would open up a new type of undersea warfare which had dramatic results, producing a new type of warrior who could be seen as the precursor of America’s feared SEAL teams.

X-MAS infiltrating the enemy harbor

A special unit, composed of both fast-attack surface craft and undersea weapons known as “human torpedoes” was formed known as the Decima Flottiglia MAS (for Mezzi d’Assalto) or X-MAS (in English, ‘Tenth Assault Vehicle Flotilla’). One man very much associated with this new unit was Prince Junio Valerio Borghese, captain of the submarine Sciré. The “human torpedoes”, as they are often called, were actually nothing of the sort as no torpedoes were involved and, while highly dangerous, were not suicide weapons. The Italians referred to them as ‘maiale’ or ‘pigs’ because these were basically miniature submarines that Italian sailors would ride ‘piggy-back’ into an enemy harbor after being brought into the vicinity by a submarine making a submerged approach. They would cut through any anti-submarine nets, approach the underside of major ships in the harbor and attach mines to the hull. Once they were safely away the mines would detonate and the ships would be crippled or sunk. The sailors would have no hope of returning to their submarine and so could either try to make it to neutral territory or simply surrender after accomplishing their mission.

In December of 1941 such an attack was launched on the British naval base at Alexandria, Egypt with the battleships HMS Queen Elizabeth and HMS Valiant being crippled, a Norwegian tanker sunk and a destroyer, HMS Jervis, being badly damaged. Men of the X-MAS, brought in by the submarine Sciré, launched a similar attack on Gibraltar in September, sinking three enemy ships. Later, operating out of an old tanker in the Spanish port of Algeciras more attacks on Gibraltar were made in December of 1942, sinking two ships and damaging two more. Two more British freighters and an American Liberty Ship were sunk in 1943 prior to the armistice. These attacks, which were almost impossible to guard against, caused considerable panic in the Allied naval forces operating in the Mediterranean. Even after the war, exploits of the Italian undersea warriors were featured in British films such as “The Silent Enemy” of 1958 and the 1962 Anglo-Italian film “The Valiant”. The X-MAS also continued its service with the Italian Social Republic after Mussolini was restored to power by the Germans and would go on to have a reputation as fiercely loyal Fascists. Their commander, Prince Borghese, would ultimately become a pariah among his fellow members of the Roman nobility for attempting a neo-Fascist coup against the post-war Italian Republic.

Capt. Carlo Fecia di Cossato

Ultimately, the armistice, division of Italy and finally the end of the war all caused confusion among the Italian submariners. Most remained loyal to the King and followed orders, turning their boats over to their former enemies, some were seized and forced into the German and later Japanese navies and some, like Prince Borghese, cast their lots with Mussolini and the Germans, to carry on to the bitter end. A most tragic case was that of Captain Carlo Fecia di Cossato, the man who sank more ships than any other Italian submarine commander at the helm of the Tazzoli. Loyal to his King above all, when the armistice came, he followed orders and even sunk seven more ships, German this time, in his new command. However, the abrupt change troubled him, becoming worse as it became clear that the Allies still considered Italy a defeated enemy and would strip Italy of her empire, even territory gained well before the Fascist Era. He was torn apart by conflicting feelings of loyalty and dishonor until he committed suicide in Naples in 1944.

When the war was finally over, with all of the confusion, bitterness and divisions which that caused, the feats of the Italian submarine campaign stand out as further proof of how wrong the popular misconception is of the Royal Italian military in World War II. Italian submarines sank about a million tons of Allied shipping from mid-1940 to 1943. This was almost as much, indeed somewhat more according to some statistics as the ultimately far larger submarine force the Imperial Japanese Navy sunk from the end of 1941 to 1945, the disparity in numbers all the more significant given that over-worked Italian industrial capacity meant that Italy could only commission 30 new boats during the war years whereas Japan commissioned 126 additional subs (not counting midget boats) during the conflict. Italy was also not very far behind the tonnage sunk by the British Royal Navy during the entire course of the war from 1939 to 1945. They played a significant part, did considerable damage to the Allied fleets and did so with skill, heroism and gallantry in the face of immense odds.

The British Submarine Campaign of World War I

During the First World War it was the submarines of Imperial Germany that certainly got the most attention in the world press. Theirs was the first major submarine campaign undertaken by any nation, the German u-boats sank the most ships by far and it was the submarines belonging to the Kaiser which pushed American popular sentiment to the Allied side and, though few realize it, they came extremely close to winning the war for the Central Powers all on their own. Whenever one thinks of the British, even with the proud and famous history of the Royal Navy which dominated the seven seas for centuries, it is usually in the context of being on the receiving end of submarine warfare rather than instigating it. This is certainly understandable given that twice in the last century, the British were driven to the brink of defeat by German submarine campaigns and, because of that, the British became masters at anti-submarine warfare. However, the British have never been without success in naval warfare under the waves as well as upon them. From the First World War to today the Royal Navy has been a major submarine power and it was in the Great War that the British produced their first submarine war heroes whose names are still household words amongst the submariners of the world.

HMS H-4

The Royal Navy entered World War I with a small collection of submarines designed to operate in coastal waters or not too far from a friendly port. These were the B, C, D, and E-class boats. It is a credit to the men that sailed them that boats of each of these classes were to achieve success in World War I, even the oldest of the B, C and D-classes. After the war had started, a new class of coastal submarine, the H-class, was built in Canada based on an American design and with American parts (U.S. neutrality at the time prevented them actually being built in America). The H-class was a little slow to catch on but ultimately proved to be a very successful design with some boats remaining in service in World War II and with other navies into the early years of the Cold War. The wartime G-class and L-class boats were more ambitious but did not see much action. As the Royal Navy grew more accustomed to submarines and ambitious in their thinking, these boats represented a step in the process toward the design of fleet submarines intended for major offensive operations. Continuing in that were the J-class, the very “creative” K-class which was steam-powered and the very fierce-looking M-class which resembled a sort of miniature, submersible battleship. The K-class proved problematic and only one M-class boat was clear for sea before the war ended and it was kept far from the action for fear that the Germans would copy the design for their own boats.

Probably the most successful British submarine design of World War I was the E-class. It is the type of boat most imagine when they think of British submarines from the First World War and it no doubt helps that all three of the most famous British submarine commanders of the Great War skippered E-class boats. They were small but sturdy and meant business with, unusually, bow, stern and beam torpedo tubes. A deck gun, originally lacking, was added in the course of the war. These, as with most British submarines tended to operate in the North Sea, the Baltic Sea and the Mediterranean Sea. Long-range offensive submarine operations were always going to be rather limited for the British since their boats tended to be limited to coastal range and in areas such as the North Atlantic they had few potential targets since the domination of the Royal Navy surface fleet tended to sink or keep in port most German merchant ships and, because of the German submarine campaign, there was always the danger of “friendly fire”. The terrible toll taken by German u-boats meant that when any British warship spotted a submarine, they tended to shoot first and ask questions later.

Centenary RN submarine flags

It was World War I which saw the birth of the British submarine tradition which continues even today. They had a spirit of reckless courage and tenacity born of adversity. The salty, old sea-dogs of the Admiralty were slow to accept the submarine as the formidable weapon of war that it is. Rightly proud of their massive battleships and with Britannia having ruled the waves for so long, such an innovation seemed unnecessary at best. Submarines were something generally associated with the enemies of the British Empire. The very first submarine attack (which failed) was made during the American War for Independence by the rebel colonists against HMS Eagle. Likewise, the original Holland-class boats had first been designed with the intention of their being used by the Fenian Brotherhood of Ireland to launch sneaky attacks on British shipping. A vessel that slipped, unseen, beneath the waves and which could attack an enemy unawares also seemed rather underhanded to the British sense of honor and chivalry. One British admiral even went so far as to denounce the submarine as “damned un-English!” while another suggested that, with the Germans in mind, all submariners should be considered pirates and hanged if captured. The British underwater sailors did not take kindly to this comparison and so decided to wind up the admirals by flying the Jolly Roger pirate flag after a successful cruise. That little show of defiance became a Royal Navy submarine tradition and when the HMS Conqueror returned home after sinking the Argentine battle cruiser General Belgrano in the Falklands War, she flew a Jolly Roger of her own design. (this, by the way, was the first and so far only nuclear submarine to sink an enemy vessel in combat)

However, the success of the German u-boats soon proved to even the most conservative British admirals that submarines were a weapon they had to take seriously and so King George V was to send his own out to do battle for King and Country. There were certain places were only submarines were able to operate effectively, areas which only they could reach and it was the British in the First World War who found out what naval experts today still know to be true; the best weapon to use against a submarine is another submarine. Three German u-boats were sunk by obsolete British C-class submarines, D-class subs sank two u-boats, the E-class sank five and British mine laying submarines accounted for a large number of destroyed German u-boats as mines took the heaviest toll of all on the Kaiser’s underwater fleet. The three primary area of operations for British submarines was the North Sea and waters adjacent to the British Isles, the Baltic Sea and the Mediterranean Sea. The North Sea would see the least success for, not only was it dangerous due to the threat of the German fleet and the presence of German submarines but also, because of this, was an area in which British ships could be just as dangerous to British submarines.

Sir Max Horton in 1940

Nonetheless, it was in home waters that the British boats scored their first success when Lt. Comm. Max Horton, captain of HMS E-9, sank a German light cruiser on September 13, 1914. Within two weeks he also sank a German destroyer, a major accomplishment and earning himself the Distinguished Service Order. Sir Max Horton was well on his way to becoming the most famous British submarine commander of all time. However, these successes were the only ones for Royal Navy boats in 1914 and they lost three subs before the year was out. It was soon decided to send them into action somewhere the Royal Navy surface ships could not reach: the Baltic. Submarines would be able to slip past the Germans, get into the Baltic and, it was hoped, cut off the supplies of iron ore being shipped from Sweden to Germany and support the Russian Empire. The first three British boats dispatched to the Baltic were commanded by men who would prove to be the very best; Max Horton in E-9, Noel Laurence in E-1 and Martin Naismith in E-11. However, the E-11, the last to make the run, was spotted by German patrols and forced back. The Central Powers had not seen the last of him though.

In the Baltic, Horton and Laurence raised havoc on German shipping. Sometimes they operated together, other times independently and the Russian port of Lapvik served as their home base. Horton proved that a submarine could operate even in the frigid conditions of January as long as one did not dally too long on the surface. Laurence, in E-1, attacked and badly damaged the German battle cruiser Moltke in the Gulf of Riga, forcing the Germans to cancel their plans for a landing there. Czar Nicholas II hailed Laurence as the “Savior of Riga” and decorated him with the St George Cross. Horton, in E-9, also sank a number of German transports, minelayers, escorts and damaged the cruiser Prinz Adalbert. He too was awarded the St George Cross by the Russian Czar and took such a heavy toll on German shipping in the area that the Germans began referring to the Baltic as “Horton’s Sea”. Their success proved to the British high command that their submarines could accomplish great things and soon more were sent in, some directly and some by being broken up and sent by rail overland from Archangel. This was an area that British surface warships could not penetrate but British submarines could and soon crippled German shipping in the area and fouled up their land operations on the coast as well.

LtComm Francis Cromie

As well as practically paralyzing German merchant shipping, the British boats also took a heavy toll on the Kaiser’s navy. Lt. Comm. Francis Goodhart, commanding HMS E-8, sank the Prinz Adalbert, E-19 commanded by Lt. Comm. F. Cromie sank the light cruiser Undine and so on. Cromie, who would take command of the five boat submarine flotilla in the Baltic after Horton was withdrawn, was another major Royal Navy hero for the submariners, on one cruise destroying over 22,000 tons of enemy shipping in a single day. The Germans had the second largest navy in the world and the Baltic was practically their backyard and yet all shipping there had been totally paralyzed by a force of only five British submarines. If further proof were needed that the subs of the Royal Navy were good value for money, their operations in the Baltic certainly proved it. By 1917 successes dropped off simply because there was nothing left to shoot at and the collapse of Russia after the revolution forced the British to scuttle their boats rather than see them handed over to the Germans as stipulated in the Treaty of Brest-Litovsk.

In the Mediterranean Sea, British submarines were dispatched to once again go where no surface warship could: the Dardanelles. Based on the island of Mudros, the original British force consisted of only six Allied submarines, three of which were the pre-war, British B-class boats which were largely obsolete. However, in the hands of a talented British captain, even these boats proved capable of success and, luckily for Britain, just such a captain was tasked with making the first foray into Turkish waters, Lt. Comm. Norman Holbrook of HMS B-11. On December 13, 1914 Holbrook and his men went in, but pushing against the strong currents made progress slow and maneuvering a struggle. Nonetheless, Holbrook was able to sight a target and with one well placed torpedo the outdated B-11 sent the Turkish cruiser Messudieh to the bottom. Holbrook managed to escape though it was a nerve-shattering experience and by the time he was able to get clear and surface his batteries were totally exhausted and the engines so totally deprived of oxygen that it took thirty minutes before they could be restarted. For this stunning victory, Holbrook became the first British submariner to earn the Victoria Cross.

HMS E-14

The next to go in was Lt. Comm. Courtney Boyle in HMS E-14. He had a hard time but managed to sink a minelayer and a Turkish troopship loaded with 6,000 soldiers and a battery of artillery. After all his torpedoes had been fired, Boyle handed out rifles to his sailors and stayed on patrol, chasing another Turkish transport onto some rocks before returning home. Boyle was also awarded the Victoria Cross. Then, of course, there was the legendary patrol of Lt. Comm. Martin Naismith, later Sir Martin Dunbar-Naismith of E-11 which penetrated the Turkish Sultan’s bathtub and brought shipping to a standstill. Forced to rely on the Berlin-Baghdad railway to supply their troops holding back the Allies at Gallipoli, Naismith sent his first officer ashore to blow up a section of the railroad, putting it out of action and forcing supplies to move by the sea again with E-11 sending more ships and boats to the bottom. Naismith would also receive the Victoria Cross for his fantastic accomplishments in the Sea of Marmara and for sinking the last Turkish battleship (formerly the German vessel Prince-Elector Friedrich Wilhelm). You can read more about these exploits here.

All told, the British submarine campaign in Turkish waters had been a resounding success thanks to the skill of the Royal Navy officers and sailors. By the time it was over, they had basically wiped out the Turkish navy by 1916 and sunk about half of the entire Turkish merchant marine as well. Efforts to use submarines in conjunction with the surface fleet proved unsuccessful, epitomized by the fate of the big K-class boats, and in the later stages of the war emphasis shifted to countering the u-boat menace. In this, again, the British submarines proved highly successful, sometimes hunting on their own and, at other times, in conjunction with a surface ship. Up until 1917 only five German u-boats were lost to British submarines but from then until 1918 the British boats managed to sink thirteen of the underwater raiders. All in all, British submarines accounted for 10% of all German submarine losses, more than were sunk by aircraft or the infamous Q-ships.

HMS E-11

Today, as mentioned at the outset, the British submarine campaign of World War I remains overshadowed by their German counterparts. This is understandable given that the German campaign was larger and accounted for many more sinkings, driving Britain to within a mere few weeks of defeat. However, the submarines of the Royal Navy did have a major impact on the war, particularly in the Baltic and in Turkish waters. They proved to a doubting admiralty just how effective submarines could be and they laid the foundation for the proud submarine tradition that is still maintained today. Five Victoria Crosses were awarded to British submariners during World War I and the greatest heroes of the British submarine campaign in World War I, Horton, Laurence and Naismith, are still household words to British submariners and others around the world. In their fight for King and Country, they had more than proven their worth.

Japanese Submarine Campaign of World War II

At the outset of World War II the Empire of Japan was one of the major naval world powers with a powerful fleet of numerous aircraft carriers, battleships, cruisers and a very innovative force of submarines. In East Asian waters they had no equal and worldwide stood alongside the United States and the British Empire in having the most powerful fleets on earth. Japan possessed short, medium and long-range submarines, were not afraid to try to new things and had what was probably the best torpedo in the world at the start of the war. And yet, Japanese submarines failed to deliver results, falling far short of what they should have been able to achieve. Naval historians have studied this issue and almost invariably came to the same conclusion: Japan simply did not use their submarines effectively and thus they performed far below the awesome potential that the Japanese submarine fleet represented. In all, 190 Japanese submarines served in World War II and 129 were lost in action. In return, the Japanese subs sank 185 merchant ships and a little over 14 Allied warships. By comparison, the German submarine fleet sank over 2,500 merchant ships in the course of the war. The Italians (with fewer boats than Japan) sank 130 Allied merchant ships in the Atlantic and Mediterranean as well as 13 Allied warships. To illustrate the point another way, Allied submarines (mostly American) sank 19 Japanese submarines during the war while only one Japanese submarine ever sank an American submarine.

I-25, which bombed the continental United States

This does not mean that the Japanese submarine force was substandard; far from it. Japan showed immense ingenuity and innovative thinking in the design of their boats. It also does not mean that the threat posed by Japanese submarines to the Allies was negligible. Japan produced the largest submarine in the world during World War II as well as the submarine with the fastest submerged speed, even besting the famously high tech German Type XXI. Yet, both of these sub types came too late to ever see combat. There were Japanese submarine commanders who scored amazing victories, sinking major Allied warships and one, though it was not known until after the war, who launched the single most devastating attack in submarine history, sinking an aircraft carrier, a destroyer and badly damaging a battleship with one spread of torpedoes. Japanese subs had their weaknesses of course but also produced boats that were bigger or faster or able to dive deeper than anything the Allies had. The Japanese sailors certainly did not lack in courage, skill or training so, therefore, the only possible explanation for the disappointing results of the Japanese submarine fleet must be attributed almost entirely to how they were used. Japan had the tools and the talent but simply failed use these resources to their best advantage. Part of the problem was specific to the Japanese submarine force itself but it was also partly due to a broader failure in overall naval strategy.

With the experience of World War I, the Germans and Italians knew that the most effective way to use submarines was to focus primarily on the enemy merchant fleet and in this, as shown above, they performed extremely well. The Imperial Japanese Navy, on the other hand, was intent on using their submarines primarily against enemy warships and incorporated them into their plan for a climactic naval battle that would settle everything with one blow. This is often attributed to the great Japanese victory over the Russians at the Battle of Tsushima in which the entire Russian fleet was totally pulverized by the Japanese ships under the great Admiral Togo. Japan hoped to repeat this same success against the United States, unfortunately, the Americans refused to play by Japanese rules and that great clash of fleets, for which Japan had been saving her best ships, including the largest battleships in the world, never happened. The U.S. Navy fought at a distance mostly with airpower while most American battleships were only ever used to shell island fortifications. The United States also used its own submarines extensively against Japanese merchant vessels, effectively wiping out the entire Japanese merchant marine by the time it was all over. They too scored victories against Japanese warships, no greater success being the sinking of the Japanese super-carrier Shinano (largest warship in the world) by the American submarine USS Archerfish.

I-58, which sank the cruiser USS Indianapolis

This also reveals a lack of appreciation of the submarine in general by the Japanese naval high command. Just as Japanese submarines were not utilized to their fullest potential, Japan did not place sufficient focus on anti-submarine warfare and the American “silent service” made them pay dearly for the oversight. Other navies had tried the idea of surface ships and submarines working close together and invariably found the idea unworkable but when the big clash of fleets that Japanese naval strategists had planned for failed to materialize, no one came up with much of a substitute so that the Imperial Japanese Navy was left to simply react to whatever the U.S. Navy was doing at the time. Originally, the idea was to use submarines to scout for the surface fleet and to weaken the approaching enemy fleet where possible as the two sides came together. This accounts for the numerous Japanese submarines that were equipped with scout aircraft to increase their ability to spot the enemy fleet. However, such a confrontation never happened and so Japanese submarine strategy seemed to lose focus. What is frustrating for fans of the Japanese submarine force is that when Japanese subs were used to sink merchant ships, what most submarine experts at the time agreed was their greatest avenue of success, the Japanese boats performed very well, particularly in the less defended waters of the Indian Ocean. However, the naval high command repeatedly pulled them away for other duties.

Those “other duties” usually involved acting as cargo carriers themselves, taking supplies to beleaguered Japanese forces defending islands in the South Pacific. This is both understandable and tragic. It is understandable because the situation was desperate and any way to get any supplies to these forces in the face of American air and naval superiority over the combat zone had to be looked at. The suffering that Japanese soldiers and sailors on these islands, especially Guadalcanal, was so immense as to defy description. Wracked by starvation, exhaustion and tropical diseases, as long as the poor soldiers were not evacuated, it is understandable that any means of getting supplies to them had to be considered. However, it is tragic because they simply should have been evacuated at that point as submarines are simply not effective cargo vessels. They amount of supplies they could possibly carry would necessarily be quite small and this prevented the subs from doing their real job which was sinking enemy ships, a job they were quite good at when given the chance. Subs were also detailed to undertake operations such as shelling the U.S. coast or dropping incendiary bombs in the hopes of sparking massive forest fires which, even if successful, would not have had any major impact on the war and, again, diverted them away from what they were best suited for.

I-53

When it came to combat operations, the Japanese submarine fleet had weaknesses as well as strengths. Japan, like the other Axis powers overall, lagged behind the Allies in sonar and radar technology. Radar sets were not adapted for Japanese subs until 1944 and even then were of very poor quality which, combined with the fact that Japanese subs were necessarily large (due to the fact that they had to have a long range to fight effectively in the massive Pacific) and thus slow to dive meant that being caught on the surface, particularly by Allied aircraft, was a real danger. Likewise, Japan possessed only rudimentary passive sonar which was not as effective as that used by the Americans which, combined with the fact that Japanese submarines tended to make more noise and be less maneuverable (due to their size) put them at a disadvantage when it came to underwater operations. However, Japanese submarines also had advantages over their Allied counterparts at least for a period of time and, unfortunately for Japan, the most innovative sub types were not completed until the war had already been lost and never saw action before Japan surrendered in 1945.

At the outset of the war the biggest advantage Japanese submarines possessed was the Type 95 torpedo which had a very long range (up to 13,100 yards), packed a powerful punch and which ran on oxygen rather than compressed air which meant that it left no tell-tale trail of bubbles behind it, making it much harder to spot by surface ships before it was too late. In comparison, at the beginning of the war, the standard American torpedo was a complete disaster that frequently failed to hit its target, often failed to detonate when it did and sometimes posed a greater threat to the boat that fired it rather than the enemy. The Japanese naval technicians were also constantly working to improve their boats. The Kaidai 6 a/b type, produced in 1934-38, had the fastest surface speed of any sub in the world at 23 knots. The AM Type boats were built to carry attack aircraft and supplement the famous SenToku class boats and had the potential to be quite effective. However, only four were ordered and only two were actually completed before the high command ordered production halted to focus on smaller subs for the defense of Japan.

The gigantic SenToku-class submarine aircraft carrier

This highlights another problem of the Japanese submarine fleet which relates back to the overall problem of a lack of focus. In production as well, Japan produced a wide variety of sub types which was expensive and time consuming while never producing very many of any one type so that even the most effective boats were too few to have much of an impact. Other navies, most especially the Germans with the medium-sized Type VII, settled on one type of submarine that best fit their needs and then produced as many of them as possible. For Japan, where resources for construction were scarce, producing so many different types of submarines with orders often being cancelled before construction was complete to switch work to another type proved to be wasteful of both resources and time which, especially as the war progressed, Japan had very little of to spare. Probably the most innovative sub type Japan built during the war, the SenToku class, is an example of this. The great Admiral Yamamoto, a far-sighted commander by any standard, supported this type of submarine with enthusiasm. However, after his death, the project was put on the shelf and work was not taken up again until later in the war so that, as we know, by the time the I-400, I-401 and I-402 were put into service, none had a chance to see action.

Certainly there are two types of submarines produced by Japan which most illustrate the great potential that the Imperial Japanese Navy had for submarine warfare if only it had been properly utilized. The first is the most well known, the aforementioned SenToku class which was the largest submarine type ever built and would retain that status all the way until 1965 with the launching of the U.S. nuclear ballistic missile submarine USS Benjamin Franklin. These were huge boats built to be, essentially, submarine aircraft carriers to launch surprise air attacks on extremely distant targets that would never be expected. Their design was highly innovative and a brilliant example of the creativity of Japanese naval engineers. Each could carry two small Seiran bomber aircraft as well as sufficient parts to be used to either repair the other two or put together for a third plane. The subs were coated with a special material, passed along from Germany, to make them more resistant to underwater search gear, special equipment was developed to allow for the aircraft to be prepared for flight while the boat was still submerged so that the boat could surface, launch its aircraft and submerge again as quickly as possible to avoid detection. These boats also had the longest range of any submarine ever developed and would hold that record until the development of the first nuclear submarines by the United States. Even today, there has never been a conventional submarine with a longer range than the Japanese SenToku class.

The 'super sub' I-401

Their great range was critical as the original intention for these boats was to cross the Pacific Ocean, hopefully undetected, rounding Cape Horn, crossing the Atlantic Ocean to then launch what would essentially be terror-raids on urban targets such as Washington DC or New York City. Everyone realized that the actual damage they could inflict would be rather limited, however, the intention was to spread terror among the American populace by attacking the United States where they least expected it and where they seemed most invulnerable. It could have had a considerable impact, forcing the American military to redeploy resources to defend against attacks on areas they never would have thought to be within reach of the enemy. That was the real aim of the I-400 boats, it was a way to send a message to the Americans that Japan could hit them almost anywhere, that no coastal region was safe. However, as we know, by the time the boats were launched the situation had changed and so when finally put to sea for their first, incomplete, war cruise, their target was instead to be the locks on the Panama Canal, the destruction of which would cripple shipping in the area, make Central America a virtual ‘dead zone’ and force all ships to sail the long way around Cape Horn at the bottom of South America. The war ended before this attack could be carried out but the potential represented by the SenToku class boats was lost on no one and one of the early American guided missile submarine designs seems likely to have been based on the I-400.

The other class of submarine produced by Japan, which highlights Japanese submarine innovation and unrealized potential is less well known but deserves to be celebrated. This was the SenTaka class of which three boats were completed before the end of the war, I-201, I-202 and I-203. In terms of their design, these boats were years ahead of their time and were precursors of the design changes in submarine hulls that would most come to be associated with the age of nuclear submarines. These boats had anything that could cause drag either removed or made retractable so that they were extremely streamlined, making them much faster and more maneuverable underwater than anything the Allies had. The electric motors were twice as powerful as the diesel engines and they were equipped with high-capacity batteries that allowed for huge bursts of speed so that these boats were capable of achieving speeds of over 21 knots while submerged, something unheard of at the time. No other submarine in the world could go so fast underwater as the SenTaka class and they were also fitted with a snorkel so that they could recharge their batteries without having to surface. As a result, though they were small boats with a rather short range, they could conceivably have operated entirely submerged for the duration of their patrol which would have made them almost impossible to detect until they started sinking Allied ships. With four forward tubs and ten torpedoes with two deck guns they also packed a respectable punch for such a small boat.

The highly advanced HA-201

The I-400’s may get the most attention for being so big and scary but the I-200’s actually represent an even greater potential of Japanese submarine success. With the underwater speed and underwater endurance these boats were capable of, they would have been extremely difficult to locate and destroy. If they had been completed earlier in the war and in larger numbers they could have taken a devastating toll on Allied shipping, perhaps even playing a decisive part in the Pacific War. These little boats would have changed almost all the rules that the Allied navies were playing by and could have had a tremendous impact, possibly even affecting the outcome of the war. Who can say? However, as it happened, only three were produced before it was all over. I-201 and I-203 were taken to Pearl Harbor after the surrender where I-201 was sunk in an ordinance test and I-203 was sunk as a test target (though we can be sure the U.S. Navy studied them intensely before doing so). The I-202 was damaged in an air raid from an offshore U.S. aircraft carrier while in port and later scuttled off the Japanese coast in 1946. None saw combat but these boats perfectly illustrate the immense creativity and potential the Japanese submarine force was capable of but never fully utilized.

Finally, if all of this seems rather depressing for submarine enthusiasts, we have to keep a few things in mind. For one, the submarine force was not alone in being robbed of the chance to achieve its greatest glory. Japan famously produced the largest battleships in the world, saved for the hoped for decisive fleet battle with the United States, and none were ever able to really show what they could do in a ship-to-ship shooting match before they were sunk. It should probably also be mentioned that, like the Americans, the Japanese had little to no submarine combat experience before World War II. That does make a difference as we can clearly see what the German U-boats were able to achieve under the command of Admiral Karl Doenitz who was a veteran submarine commander who saw action in World War I as captain of UB-68. Even for the United States, while lacking the combat experience that the Germans had from World War I, it made a difference that the American naval commander in the Pacific was Admiral Chester Nimitz who, as a young officer, had commanded the USS Skipjack and held numerous submarine flotilla commands prior to World War II. He may have lacked combat experience but he certainly knew and appreciated what submarines were capable of and used them to best effect.

I-58 carrying Kaiten 'human torpedoes'

The results achieved by the submarines of the Imperial Japanese Navy are, ultimately, deemed unsatisfactory in large part because anyone can see that they had so much potential. It is not that they had no victories but that they were capable of having much, much more extensive victories if only they had been properly utilized. It should not be forgotten then that the toll taken by Japanese submarines during the war, over 900,000 GRT (gross register tons) of Allied merchant shipping, was a loss that was certainly felt by the Allies. Japanese submarines sank ten small warships, two cruisers and two American aircraft carriers during the course of the war. Let that fact sink in for a moment. That was more than anyone else has done against the U.S. Navy. The problem was simply that the Japanese naval high command refused to change their thinking when their original strategy proved unworkable. They lacked focus, building massive submarines that never saw service and tiny, suicide weapons, the famous “kaiten” which ultimately did very little damage to the enemy, rather than mass-producing a greater number of one or two submarine types such as the Germans did with the Type VII and Type IX or as the U.S. did with the Gato, Balao and Tench-classes. Japan had the largest, the smallest, the fastest, the deepest diving submarines and Japan made the most destructive single submarine attack in history. However, the lack of adaptability, technological deficiencies and a lack of focus by the high command prevented the Japanese submarine force from accomplishing much more, even, on perhaps more than one occasion, being a decisive weapon in the Pacific War.