Among the most daring of British submarine actions in World War II were those involving midget submarines. The Royal Navy had three types. Two were of more or less conventional appearance, and the third resembled a torpedo on which two riders wearing underwater breathing equipment sat astraddle. The latter type was known as the Chariot. It was capable of being steered and of making a speed of two or three knots under the water. Its explosive warhead could be removed and attached to its target. There it would be exploded by a timing device set to go off when the Chariot and its riders had gotten safely away.
Another British midget submarine was just large enough for a single man. Known as the Welman type, it was too small to carry explosives, and was used as a vehicle for landing agents surreptitiously on enemy shores.
The third type was known as the X type. At the hands of daring crews it established a distinguished combat record, most notably in action against the German battleship Tirpitz in Alten Fjord, Norway.
The Tirpitz had been a thorn in the side of the Allies since the beginning of the war. As long as there was a chance that it might take to the sea to attack Allied convoys, it was necessary for the British to maintain heavy units of the Royal Navy standing ready to intercept it. As long as Royal Navy units were thus occupied, they could not be used for other important work.
Repeated aerial attacks had failed to put the German battleship out of commission, and attacks by surface ships or conventional submarines were out of the question — the Tirpitz was 4 miles from the sea in a heavily defended fjord.
The decision was made to attempt a surprise attack using midget submarines of the X type. Each of the X craft was 50 feet long and displaced 40 tons. Two detachable 2-ton explosive charges were carried on the outside of the hull as side cargo. Each of the submarines had a crew of four, one of whom was trained as a diver — he could leave his craft while it was submerged and cut a hole through any antisubmarine net that might block the way.
Six of the X craft left Scotland for Norway in September, 1943, in tow of conventional submarines. Of the six, two were lost on the way, and a third suffered a mechanical breakdown that kept it from joining in the attack of September 22.
The X-6, commanded by Lt. Donald Cameron, was the first of three X craft to make their way up the fjord. When it arrived in the vicinity of the Tirpitz, Cameron brought it to the surface to orient himself. Just as he did, there occurred one of those fortuitous events which no writer of fiction would dare intrude into the plot of his story. When the X-6 gingerly broke the surface, Cameron saw that the protective nets surrounding the Tirpitz were opening to admit a boat carrying fresh water. He ordered the X-6 down again and with full speed ahead he boldly forged past the nets before they closed.
Once inside the nets, Cameron had to surface again to get a bearing on the Tirpitz. This time when the midget submarine surfaced it was seen by the Germans, and a fusillade of gunfire rained down on it. Cameron quickly got his bearings, submerged again, and piloted the X-6 beneath the warship's hull. There he detached his explosive side cargoes, with their time fuses running.
Continuing on beyond the Tirpitz, the X-6 struck the far side of the protective net. Reversing course, the X-6 smashed into the hull of the warship. At this point Cameron decided that since he had accomplished his mission of placing the explosives, there was no use in sacrificing his own life and the lives of his crewmen in the X-6. He brought his craft to the surface beside the Tirpitz, gave the order to abandon ship, and opened the submarine's hatch.
As he did so, a German sentry lobbed a hand grenade over the side of the battleship and down into the X-6. With astonishing presence of mind a crewman behind Cameron picked it up and tossed it out again before it exploded.
The X-6, its seacocks open, flooded and sank. Cameron and his crew were taken prisoner.
Meanwhile the X-7 commanded by Lt. Godfrey Place, made its way into the net-enclosed area around the Tirpitz by dint of being lifted over the net by the explosion of a German shell. Proceeding underwater, Place took the X-7 under the Tirpitz's keel and detached his explosives. Unable to make his way out of the net enclosure again, Place surfaced and abandoned his sinking submarine, and was followed by one of his crewmen. The other two of his crew were lost.
The third midget submarine to reach the Tirpitz's nets was the X-5. Apparently hit by a German shell in the holocaust stirred up by the X-6 and X-7, it sank with all hands.
With the six surviving British submariners being held as prisoners on board the Tirpitz, their explosive charges detonated, lifting the stern of the German warship an estimated 6 feet in the water. Though it did not sink, it was so seriously damaged that it was never again seaworthy.
The Germans carefully concealed the Tirpitz's damaged condition from the British and, as a result, much of the potential profit from the daring and successful attack by midget submarines was nullified. British fleet units, not knowing that the German battleship was crippled, continued to stand guard in case it should put out to sea — something that it could never again do under its own power after the attack by the midgets on September 22, 1943. Later in the war, planes of the Royal Air Force, dropping specially designed "Two-ton Tessie" bombs, capsized the Tirpitz, thus manifestly ending the threat it posed to Allied shipping. Only after the war did the Allies learn that the threat had actually been ended by the X-6 and X-7.
For their action in command of the successful midgets, Cameron and Place were each awarded the Victoria Cross.
A modification of the X craft was used by the British in an operation against the Japanese. On July 30, 1945, the XE-3, commanded by Lt. I. E. Fraser, made its way into the harbor of Singapore and there with much difficulty the six mines it carried were attached to the hull of the Japanese cruiser Takao. The XE-3 escaped again to its mother submarine, HMS Stygian, and its mines blasted a hole 60 feet by 30 feet in the Takao's hull.
Japan began its participation in the war with sixty-three ocean-going submarines — six more than Germany's total of fifty-seven of all types at the outbreak of hostilities two years before in 1939. With an additional number of smaller submarines the Japanese submarine force was larger than the submarine force of the United States Navy's Pacific Fleet. With it Japan expected both to protect its own coasts and shipping from attack by surface ships and to attack the Pacific Coast shipping of the United States.
Model 93 Torpedo — Long Lance
Although the Japanese submarines were criticized as being too big and awkward, Japan entered the submarine war with one decided advantage: it had a torpedo that would work. And what a torpedo it was!
Designated the Model 93, it was powered by oxygen. Other nations had recognized the potentialities of an oxygen-fueled torpedo, and Britain had even attempted to develop one, but the results of its experiments were discouraging. Oxygen was a tricky fuel indeed, because if it became mixed with even trace amounts of oil, a disastrous explosion was the result.
After several mishaps Britain abandoned its experiments with oxygen as a torpedo fuel.
Japan, however, did not. The Japanese naval attaché in London acquired information about British successes and failures with oxygen. Building on this information, Japan went on to succeed where Britain had failed.
The result was the superlative Model 93 which overshadowed the Mark 10 torpedo with which many United States submarines were armed at the outset of the war. The Mark 10 had a range of 1¾ miles and a speed of 36 knots; the Japanese torpedo, running at the same speed, had a range of 22 miles (for which it became known as the "long lance"). Where the Mark 10 carried 497 pounds of explosive, the Model 93 carried 991 pounds.
The advantage the Japanese gained in using the "long lance" torpedo was decisive in their naval victory in the Battle of Savo Island near Guadalcanal in 1942. In it the Model 93, fired from Japanese surface ships, sank one Australian and three American cruisers.
In other actions single "long lance" torpedoes tore the bows off the cruisers New Orleans and Minneapolis and knocked the cruiser Chester out of action for a year.
With "long lance" torpedoes in their tubes, Japanese submariners entered the war with an ace of trump in their hand. However, though they enjoyed some success, they never entirely capitalized on the potentialities of the submarine. Instead of conducting deliberate and sustained submarine warfare against the sea lanes of-the Allies, the Japanese submarine service embarked on a number of wild-shot operations.
One of these took place in Australian waters in May, 1942. The Japanese submarines I-22, I-24, and I-27, each carrying a midget submarine, arrived off the port of Sydney. There they released their midgets, which made their way into Sydney harbor. One fired a torpedo that just missed both the cruiser USS Chicago and the destroyer USS Perkins. The two American warships quickly got out of the harbor and sank one of the midgets on their way. An Australian harbor patrol craft sank another, and the third was destroyed by the premature explosion of one of its own torpedoes.
In another irregular operation the I-25, commanded by Lt. Comdr. Meiji Tagami, left the Japanese naval port of Yokosuka in August, 1942, bound for the northwest coast of the United States.
On board was a scouting aircraft. In September the plane made two attacks on Oregon, dropping incendiary bombs which set fire to forest tracts. They were the only air raids ever made on the United States and the harm they caused was not great.
On its return to Japan the I-25 sank two American oil tankers, and — on October 11, with its last torpedo — the submarine USS Grunion.
The Japanese submarine I-168, commanded by Lt. Comdr. Yahachi Tanabe, scored an important one of the limited number of naval successes of the Japanese submarine service. It came in support of the Japanese attack on Midway Island in June, 1942. In the battle, which was a turning-point defeat for the Japanese, the aircraft carrier USS Yorktown was hit and disabled by aircraft from the Japanese carrier Hiryu. (The Hiryu's pilots, returning jubilant with success at the end of their mission, found that their own carrier had been sunk while they were gone.)
Orders were flashed to Tanabe on the 1-168, directing him to find and sink the damaged Yorktown. The Japanese submarine captain found it lying dead in the water about 150 miles northeast of Midway. Undeterred by six protecting destroyers, Tanabe maneuvered into position and fired four torpedoes, which sent the American carrier to the bottom. The destroyers attacked the I-168 with depth charges and with gunfire when Tanabe surfaced to gain needed air for his batteries, but the submarine escaped. Unlike many of his submarine-captain colleagues of the Imperial Japanese Navy, Tanabe survived the war.
On January 18, 1943, Japanese shipbuilders laid the keel of what was to be the largest submarine ever constructed, larger even than the prewar K and M boats of Britain and the giant Surcouf of France. When completed the Japanese leviathan, the I-400, displaced 5,220 tons, putting it in the same weight class as a light cruiser.
Manned by 144 officers and men, it carried no fewer than three scouting planes. Its armament consisted of a 140mm deck gun and eight torpedo tubes for which it carried twenty torpedoes.
It was 400 feet long and was capable of making more than 18 knots on the surface and 6 knots submerged. At a sustained speed of 14 knots it was capable of traveling a distance equal to one and a half times around the world at the equator without refueling.
Original plans called for eighteen of the giants to be built, but construction was begun on only five, and of these five only three were completed by the end of the war. None ever got into action. One was sunk in waters off its base at Sasebo, and the other two were handed over to the United States after the surrender in 1945.
Kaiten — Manned Torpedo
While the I-400 and its sisterships were being constructed, the Japanese began the construction of other submarines of unusual size. The size in this case was small — the submarine under development was to carry only one man.
Designated kaiten, meaning "heavenly change," the one-man submarines were actually modifications of the long-lance torpedoes. The 30-foot length of the long-lance was extended to 54 feet. In the middle of it was constructed a small pilot's compartment, complete with controls and a periscope. At first the Japanese considered making it possible for the pilot to abandon his kaiten before being blown up with its 3,000-pound warhead, but in the end it was decided that this was an impossible luxury — the pilot would have to die in the explosion. (The idea of a suicide submarine was not exclusively Japanese, incidentally. The Germans, too, considered such a weapon, and went so far as to construct high-speed one-man boats for the purpose. They eventually discarded the idea.)
Manufacture of the Japanese suicide torpedo-submarine was begun in 1944, and there was no lack of volunteers for the one-way trip to death and glory. The first attacks were carried out on November 20, 1944, at Ulithi Atoll in the Pacific where one of the kaitens struck the oil tanker USS Mississinewa. At another time and place the destroyer Underhill and the dock landing ship USS Oak Hill fell victim to the manned torpedoes also, but the overall effect of the kaitens was disappointing to the Japanese. For their modest measure of success, eighty of the suicide craft were lost. Even more important, eight of the submarines which carried the kaitens to the vicinity of their targets were lost also.
Two weeks before the end of the war a Japanese submarine, the I-58, fired a spread of long-lance torpedoes which sank the USS Indianapolis. The sinking came on July 29, 1945, as the cruiser was on its way to the Philippines. It went down fifteen minutes after the torpedoes struck, and no SOS went out.
Because of a blunder the disappearance of the cruiser went unnoticed at American naval headquarters. As a result, the survivors of the Indianapolis's crew of 1,196 were in the water for four days, during which they suffered almost every conceivable sort of horror, from blistering tropical sun to shark attack, maddening thirst, and insanity. When the survivors were discovered, entirely by accident, there were only 316 left.