In the long run, it might have been better had the torpedoes failed absolutely in 1942. Complete failure would have compelled immediate and decisive action to identify and correct the various mechanical flaws. Instead, the weapons sometimes functioned properly, while in many other instances they appeared to do the job when they had actually exploded prematurely and harmlessly. Intermittent and apparent success perversely guaranteed that the deficiencies would not be discovered all at once. The torpedo problem was solved in fits and starts, over a period of two years, against the obdurate resistance of bureaucrats and engineers in Washington and Newport, Rhode Island. Meanwhile the submarine crews risked and sometimes gave their lives to carry unreliable weapons into enemy waters, all the time wondering whether their suspicions were justified. On October 20, 1942, the Trigger, while submerged at a depth of about 100 feet, fired a torpedo at an unescorted tanker. The weapon’s rudder jammed and it ran in a circle, a failure that should have destroyed the Trigger. But the boat was saved by a second defect in the boomeranging torpedo. The detonator, which should have detected the Trigger’s magnetic field and activated the warhead upon reaching its strongest point, instead exploded at a distance great enough to leave the boat intact. The weapon had suffered two unrelated failures, the second providentially neutralizing the first. Meanwhile the enemy tanker went on her way, probably unaware that she had been fired on. The incident would have been laughable were it not so potentially deadly.
The first problem to be isolated and solved was the Mark 14’s tendency to run about 10 feet deeper than set. It had required initiative on the part of Charlie Lockwood in Freemantle, Western Australia. His correspondence with the bureau in Washington brought a high-handed dismissal, replete with technical data purporting to show that the complaints were unwarranted. In June 1942, Lockwood took matters into his own hands by designing a series of tests. These conclusively demonstrated that the weapons were running about 11 feet deeper than their settings. With additional pressure from Admiral King, the engineers in Newport finally conducted their own tests and concluded that the Mark 14 was running 10 feet deeper than set. That was easily corrected by changing the depth setting, in most cases to zero.
ON THE STORMY MORNING OF JANUARY 21, 1943, a flying boat named the Philippine Clipper descended to 2,500 feet over mountainous terrain in Mendocino County, California. The big aircraft was a former Pan Am airliner, pressed into service by the navy to fly high-ranking officers between Hawaii and the mainland. The pilot had lost his way in the impenetrable white murk. Aiming for San Francisco Bay, he was more than sixty miles off course to the north. He flew directly into the side of a mountain. No one survived. Among the dead was Admiral Robert English.
Nimitz tapped Charlie Lockwood as the new commander of the Pacific submarine force. It was a fortunate choice. Lockwood, more than any flag officer in the submarine fleet, had recognized and advocated a reconsideration of prewar doctrines and tactics. Arriving in Pearl Harbor to take up his new command in early 1943, he discovered to his satisfaction that the submarine base had been expanded and improved. New construction was apparent everywhere. Nimitz’s CINCPAC staff had moved out of the submarine base and into a new headquarters building, freeing up space for Lockwood’s operation. The new COMSUBPAC moved into a large white house on Makalapa Hill.
In December 1942, Admiral Christie had been relieved of command of Task Force 42 in Brisbane and sent to Newport to take command of the Naval Torpedo Station. Bitterly opposed to the assignment, Christie could do nothing to stop it. He had defended the torpedoes and obstinately dismissed the rising chorus of complaints against them. Now he would come under pressure to reform the obstruction at its source. Arriving in Newport, he had hardly unpacked his bags before receiving orders sending him back to Australia to take command of all submarines in the Southwest Pacific Area. He would serve in that position, subordinate to Lockwood, until November 1944.
Continued reports of premature explosions of torpedoes prompted Lockwood to wonder whether the Japanese had developed some countermeasure. Had the enemy devised some means to trick the torpedoes into exploding early? Many skippers became so distrustful of the device that they advocated disabling it in favor of the contact detonator. Lockwood, though sympathetic, was reluctant to allow such a drastic measure. The magnetic detonator was one of the navy’s most prized technological innovations in the interwar period. It had influential proponents, including Mush Morton. Though it might not be entirely reliable, it also did not fail in every instance. The unreliable detonator was not disabled in favor of the contact detonator until late 1943 (except on the initiative of individual captains). In any case, the contact exploder was also unreliable.
In Australia, Christie refused to entertain grievances about the torpedoes. In his view, skippers who blamed their weapons were blowing smoke to obscure their own faults. Airing complaints about the torpedoes, he said, would jeopardize the collective morale and self-confidence of the submarine force. He was not entirely unbiased. For more than twenty years, dating back to a postgraduate program at MIT in the early 1920s, Christie had been personally involved in the development of the magnetic detonator and other torpedo technologies. In the mid-1930s, he had run the torpedo section of the Bureau of Ordnance. His fingerprints were all over the Mark 14. After the war, he told Samuel Eliot Morison that torpedo failures were “largely a question of upkeep on the part of repair and operating personnel. . . . I have always contended that, given a conscientious and experienced torpedo gang, much of the poor performances in 1942 would have been eliminated.”68 When William J. Millican of the Thresher reported that he had fired on a Japanese submarine and “clinked ’em with a clunk” (that is, the torpedo was a dud), Christie ordered that no written mention of the incident should appear in patrol reports or endorsements.69 The discussion boiled over into a full-scale shouting match.
Writing to Lockwood that fall, Christie avowed that “torpedo performance here is steadily improving” and doubted the credibility of reported prematures and duds. Commanding officers, he added, had in some cases recounted torpedo failures “under conditions where it was impossible that he could see it.”70 The suggestion that captains were deliberately lying was too much for Lockwood. He slapped Christie down in a letter laced with sarcasm. “Thank you for your letter,” he wrote. “From the amount of bellyaching it contains, I assume that the breakfast coffee was scorched or perhaps it was a bad egg. . . . [T]he facts remain that we have now lost six valuable targets due to prematures so close that the skippers thought they were hits. . . . Sorry to note that you believe the operating personnel is usually wrong about what they see, or think they see. Your Bureau training has not been wasted.”71 A shaken Christie lost no time in apologizing, but he would never fully acknowledge the egregious flaws of the Mark 14.
On a quick trip to Washington in early 1943, Lockwood threw down the gauntlet. He spread his criticisms widely through the Navy Department, presenting his case with pungent sarcasm. To a senior member of King’s staff he said, “If the Bureau of Ordnance can’t provide us with torpedoes that will hit and explode, then for God’s sake get the Bureau of Ships to design a boat hook with which we can rip the plates off the target’s side.”72 That salvo touched off a heated exchange with Admiral William H. P. “Spike” Blandy, chief of the Bureau of Ordnance. Blandy admitted that engineers at the Naval Torpedo Station had been slow to identify and correct the problems, but complained in turn that the fleet had resisted assigning good men to work in weapons development programs. “We sadly lack submarine officers in the bureau,” wrote Blandy, “and you won’t get the best results from your torpedoes until you let me have some. . . . As you know yourself, every time I try to get some submarine officers who also know torpedoes, I am usually offered somebody who hasn’t made good in the boats themselves, and my efforts to get a good man are usually met with the objection that he is too valuable as a commanding officer.”73
JAPAN’S DECISION TO LAUNCH A WAR in the Pacific had b
een motivated, above all, by the desire to possess the oil fields of Borneo and Sumatra, as well as the rubber plantations and tin mines of Malaya and other territories under Dutch or British control. Control of those prizes would avail nothing if Japan could not command the sea-lanes linking them to the home islands. Impoverished in natural resources, Japan’s economy and war-making potential were perilously dependent on imported iron ore, bauxite, rubber, copper, zinc, and especially oil. Japanese fighting forces throughout the region required massive and sustained logistical backing, which could be supplied only by sea. The entire system could be held hostage by a fleet of aggressive and well-equipped submarines operating against Japan’s critical interior sea routes. The freighters and tankers that would ply the sea routes would need to be protected at all costs; otherwise Japan’s entire imperialist project would collapse like a sand castle in the surf. That is in fact what happened in 1944 and 1945.
All of this was clearly foreseen prior to the war, but Japanese naval leaders never made any real study of this problem, nor did they develop more than rudimentary capabilities in antisubmarine warfare (ASW). The nation’s previous naval wars had been relatively short and decisive affairs in which commerce protection had never become a vital consideration. The samurai warrior culture esteemed offensive warfare more than defensive considerations, and no ambitious officer would waste his time specializing in the dreary and unglamorous business of protecting marus. There was no percentage in it; no hope of promotion or influence. Japan’s fine destroyer fleet trained intensely for night torpedo attacks against enemy warships, but escorting convoys of merchantmen was never more than an afterthought. Antisubmarine warfare never gained a strong voice at the Navy Ministry or the Naval General Staff, and no unit was tasked with full-time convoy duties until months after the war began. As shipping losses mounted in 1944, the manifest necessity of convoys ran up against the need to keep the remaining ships circulating briskly. Even as entire convoys were slaughtered at sea, the Japanese navy was reluctant to put talented officers to the problem. The leadership could not bring itself to admit that antisubmarine warfare was a professional subspecialty requiring staff analysis, weapons development, and training. Atsushi Oi, one of a handful of staff officers assigned responsibility for antisubmarine warfare, was often told by skeptical colleagues that “escort-of-convoy was common sense to a navy officer.”74
Effective convoying required, at a minimum, a scheme of cooperation between escorts and cargo ships. But Japanese naval personnel insisted on treating merchantmen with contempt. In the navy’s hierarchy, recalled one veteran merchant mariner, he and his shipmates “were lower than military horses, less important than military dogs, even lower than military carrier pigeons.”75 On one ship with a mixed crew, all merchant mariners were confined below, while only Etajima (naval academy) graduates were allowed to take in the sun and sea air on deck. “That was their attitude. There was no sense you were all fighting together. You can’t win with such an attitude.”76 In the second half of 1943, Japan brought heavy cargo ships to Truk under escort, and then dispersed cargos into small, cheaply built wooden barges called “sea trucks” for distribution to island garrisons. As the toll of Japanese shipping mounted in 1944 and 1945, decades-old vessels were hauled out of mothballs. Many were in such disrepair that their crews thought them unseaworthy even if they were not attacked. Ignobly, the Japanese employed Red Cross relief ships to carry troops and war materiel.77 American submarines let them pass unmolested, as required by treaty law.
In late 1943, the Japanese detected a disturbing improvement in the performance of American torpedoes. Sinkings mounted rapidly, surpassing 300,000 aggregate tons in the month of November 1943.78 A dependable Mark 14 torpedo was the single most important factor in the mid-war surge, but there were several others. Audacious and seasoned executive officers and third officers were promoted to command their own boats. The submarine fleet was equipped with better surface-search radar systems, better sonar, a better periscope, and eventually the Mark 18 electric torpedo, which left no wake. The code-breaking fruits of Pearl Harbor’s communications intelligence hub (Fleet Radio Unit Pacific or “FRUPAC”) were employed to guide submarines, by long-range radio broadcast, directly into the track of oncoming convoys. FRUPAC’s Merchant Marine Unit charted Japanese shipping movements daily, and could provide timely and reliable intelligence of departures, destinations, noon positions, and the whereabouts of enemy minefields. In December 1943, the U.S. Navy’s intelligence division could confidently report that “the enemy’s sea lanes are under constant and forceful attack. . . . Our submarines range unhindered through the maritime vitals of ‘Great East Asia,’ and for more than a year and a half they have been exacting a much heavier toll in merchant tonnage than Japan’s shipyards can possibly replace.”79 That was true in spite of the numerous disappointments of the early submarine campaign, and sinkings were on the verge of rising dramatically. In early 1944, Japanese shipping losses consistently surpassed 200,000 gross tons per month.
In the last eighteen months of the war, the American submarine force was finally deployed in a thorough campaign to blockade the home islands of Japan. American skippers came to know every bay and inlet of the Japanese coast, better even than they knew their own home shores. The marus were reduced to making desperate port-to-port dashes, with balsa logs and rafts triced down on deck to provide flotation when their ships went down. They took increasingly circuitous routes to avoid the most infested waters. Rather than cross the Yellow Sea, the marus crept along the coast of Korea and down the coast of China, seeking refuge in shallow waters or behind coastal islands. A dark night no longer offered asylum. Equipped with steadily improving radar systems, American submarines could identify and stalk unseen enemy ships to a radius of forty miles. Running on the surface at four-engine speed, at a pace nearing or exceeding 20 knots, and safe from aerial observation, the submarines attacked even the most strongly escorted convoys with impunity. With new sonar detection systems, submarines penetrated minefields to enter the Sea of Japan and severed the last remaining tendons connecting the home islands to the resource-rich territories of Korea and Manchuria.
The asphyxiation of Japan’s sea communications was in itself sufficient to destroy the nation’s capacity to wage war, a point laid bare by a few statistics on the oil situation. With negligible domestic oil production, Japan’s imperialist project could not survive without a stable supply from the conquered territories of Borneo and Sumatra. Japanese naval planners had predicted self-sufficiency as soon as the captured oilfields were brought up to full production. But the vital artery was to be sustained by a handful of slow (and thus vulnerable) oil tankers. In 1942 (a frustrating year for the American submarine force, as we have seen), the Japanese lost just four tankers. In 1943, the figure rose to 23; in 1944, it was 132; and in the first eight months of 1945, the Allies destroyed 103 Japanese tankers. In 1942, 40 percent of East Indies crude oil production safely reached Japan. In 1943, that proportion declined to 15 percent; in 1944, it fell to 5 percent; and after March 1945, not a single drop arrived on Japanese shores. Crude oil reserves, having peaked at twenty million barrels in early 1941, diminished to fewer than a million in the fourth quarter of 1944.80 The Japanese met the crisis with a crash tanker-building program, and by converting ordinary merchant ships to carry oil. But shipbuilding required steel, while the reverse was equally true—the steel mills required coking coal and iron ore that must be imported by sea. From a 1943 peak of 7.8 million tons, ingot steel production plummeted to a per-annum production rate of about 1.5 million tons in 1945, or about 15 percent of the industry’s production capacity. As the aerial bombing campaign reached its zenith in 1945, devastating Japan’s transport system and industrial areas, the nation’s war production had already been hollowed out by the interdiction and destruction of its sea communications.
By the war’s end, the Pacific submarine force would sink more than 1,100 marus, amounting to more aggregate tonnage than Japa
n had possessed on December 7, 1941. With fewer than 2 percent of all naval personnel, the submariners could claim credit for more than half of all Japanese ships sunk during the war, and 60 percent of the aggregate tonnage. Although their primary strategic purpose was to destroy the enemy’s seaborne commerce, the submarines also sent 201 Japanese warships to the bottom, with a combined tonnage of 540,192.81
These triumphs were not achieved cheaply. Fifty-two World War II submarines “remain on patrol,” to borrow the submariners’ poignant euphemism. Forty-one boats are known to have been destroyed by enemy attack. The submarine force was very small when compared to the rest of the navy—the submarine service had a wartime average personnel strength of just 14,750 officers and enlisted men. About 16,000 men altogether made at least one war patrol. Of these, 375 officers and 3,131 men gave their lives—a mortality rate of 22 percent, higher than that for any branch of the armed services. It is perhaps understandable, then, that the submarine force demanded and received recognition of its tremendous contribution to the defeat of Japan. Charlie Lockwood, after the war, told a former skipper who had accepted a post on the faculty of the Naval Academy, “Now don’t teach those midshipmen that the submariners won the war. We know there were other forces fighting there, too. But if they kept the surface forces and the flyboys out of our patrol areas we would have won the war six months earlier.”82
* Maru was the suffix applied to the names of Japanese freighters, troopships, and oil tankers. American submariners employed the term to refer to any such vessel.