In the summer of 1945, when the tremendous momentum of our drive was rolling up the islands of the Pacific and bringing close the planned invasion of the Japanese homeland itself, the United States Navy established a mission to determine the position of the Japanese in the field of naval technology.
How did the design and construction of their warships compare with ours? What range and power had their guns? How heavy was their armor and what was its metallurgy? Were they ahead of us in electronics development? The Navy wanted the answers to these and many other technical questions.
To obtain the desired information, investigators had to enter Japan with the Occupation forces, before manufacturing plants, equipment, materials, and records could be destroyed and experienced personnel dispersed.
The U. S. Naval Technical Mission to Japan, better known as NavTechJap, was established on August 14, 1945, by an order of the Commander in Chief and Chief of Naval Operations. The purpose of the Mission was to survey all Japanese scientific and technological developments of interest to the Navy and Marine Corps in the Japanese Islands of Kyushu, Shikoku, Honshu, Hokkaido; in China; and in Korea south of latitude 38°N. This involved the seizure of intelligence material, its examination and study, the interrogation of personnel, and, finally, the preparation of reports which would appraise the technological status of the Japanese Navy and Japanese industry.
The surrender of the Japanese in mid- August required that the basic organization be equipped and prepared to leave Pearl Harbor by September 1, 1945—approximately two weeks after the directive establishing the Mission had been issued—in order to obtain the advantages of early exploitation of targets. The nucleus of the initial organization was recruited from technical and language personnel attached to JICPOA (Joint Intelligence Center, Pacific Ocean Area) and technical personnel flown to Pearl Harbor from various continental naval activities. This group was designated JICPOA Team No. 29 and consisted of approximately 105 officers and 84 enlisted men. It sailed from Pearl Harbor on September 1, 1945 aboard the U.S.S. Shelby (APA 105) and was part of the convoy which entered Sasebo Naval Harbor on September 23, 1945, in the initial occupation of Kyushu.
Within a period of three weeks from the initial landing at Sasebo, technical intelligence teams stemming from the headquarters of the Mission at Sasebo had entered Tokyo, Yokohama, Yokosuka, Kure, Hiroshima, Osaka, Nagoya, Kyoto, Maizuru, Matsugawa, Kochi, Fukuyama, Okayama, Nagasaki, Kumamoto, Moji, Shimonoseki, Kagoshima, and Fukuoka, with or shortly after the initial landing of the Army or Marine units in these cities.
Within four weeks technical intelligence teams were established in or within easy reach of all major industrial centers in the main Japanese Islands, and teams had entered China and Korea. The purpose was to spread available talent at headquarters out quickly so that qualified representatives of the Mission would be available in all parts of the Empire to evaluate targets, to interrogate Japanese naval and civilian personnel, and to report, in summary form, the intelligence value of that area. A secondary purpose was to provide qualified Navy personnel in each area who could clear all naval equipment for demolition and who could, when necessary, instruct Army or Marine personnel in methods of demolition.
The magnitude of the task assigned to the Mission presented almost immediately two major difficulties. One was the increasing necessity for well-equipped and competent technicians to cover the vast field of Japanese naval developments. Qualified specialists and experts, therefore, were requested and received from the Bureau of Ships, the Bureau of Ordnance, the Bureau of Yards and Docks, and the Bureau of Medicine and Surgery.
The second important difficulty confronting the Mission was one of location. Sasebo, located on the island of Kyushu, is in a provincial and agricultural area of Japan, as far removed from the scientific and technical centers in the vicinity of Tokyo as it is possible to be and yet remain on the main islands of the Empire. It was remote from all the industrial centers of Japan; communications were poor; and all intelligence units operating in the Empire, such as U.S. Strategic Bombing Survey, the Compton-More- land Scientific Survey, the Air Technical Intelligence Group, and the Military Intelligence Section of SCAP, had headquarters in Tokyo. The function of the Naval Technical Mission to Japan had to be correlated with the activities of these groups in order that all intelligence units could profit from the disclosures obtained by each. Consequently, on November 1, headquarters of the Naval Technical Mission was transferred to Toyko.
At first the entire complement of officers and men was billeted aboard the barracks ship Blackford, but increase of personnel required more facilities. So an additional barracks ship, APL-46, was allocated by Commander Fifth Fleet. Subsequently, quarters were obtained for the Chief of the Mission in the Imperial Hotel in Tokyo, and for 40 senior officers in the Dai Iti Hotel, both hotels being Army billets.
All logistic support for the Mission, such as food and quarters for the overflow of officers and men billeted in Tokyo, Army winter uniforms for all personnel, and maintenance of automotive equipment were provided by the Army.
By November 1, 1945, the Mission had grown to approximately 295 officers, 125 enlisted men, and 10 naval technicians. Among the officers was a delegation of approximately 23 British technical specialists and language officers, an able and experienced group which cooperated effectively on many difficult investigations. There was a constant turn-over in the personnel attached to the Mission due to the arrival of specialists and the detachment of officers having completed their assignments.
Under the Chief, the Mission was divided into two departments, Executive and Technical. Under the Executive Officer were several assistants and section heads in charge of liaison service, administrative files, personnel, supply, transportation, communications, shipment of seized enemy material and documents, and language services. Under the officer-in-charge of the Technical Department was an assistant officer-in-charge, and section heads in charge of the Ships, Electronics, Ordnance, Medical, Special, and Petroleum Sections, as well as the Atomic Bomb Medical Group.
In addition, there were two other activities in the Technical Department. One was the Progress and Reports Section which was charged with the responsibility of filing intelligence material, and with the receiving, editing, typing, and final printing of the technical reports of the Mission.
The other activity in the Technical Department was designated Technical Liaison, G-2, SCAP. Immediately on arrival of the Mission in Tokyo, an officer was detailed as NavTechJap Liaison Officer to Military Intelligence Section, G-2, SCAP. This officer attended all General Headquarters, SCAP policy-forming conferences, and meetings which affected naval intelligence. He cleared all naval intelligence targets with, and passed all intelligence material and information gathered by the Mission to, the Military Intelligence Section, G-2.
In addition to the Technical and Executive Departments, a separate Special Intelligence Group was maintained. This group was employed in the exploitation of such nontechnical targets as were requested by higher authority, or as were left uncompleted on the departure from Japan of the U. S. Strategic Bombing Survey.
The primary objective of the Mission was to find, investigate, examine, evaluate, and report on Japanese naval equipment, documents, and practices. Before the cessation of hostilities, the Office of Naval Intelligence was ready with a publication: “Intelligence Targets—Japan.” This was a series of pamphlets stating the Navy Department’s requirements for intelligence exploitation in Japan. It represented the coordinated demands of Cominch and CNO, the Bureaus of Ships, Ordnance, Aeronautics, Yards and Docks, Medicine and Surgery, Office of Research and Inventions, Naval Research Laboratory, and other technical activities. The targets contained therein emphasized naval interest, entirely; nevertheless, they had also been coordinated with the War Department Intelligence Collection Committee for such instances where War Department interests paralleled those of the Navy.
What sort of things were the Bureaus interested in? What was the nature of some of these individual targets? “Intelligence Targets—Japan” was a secret publication. However, as any ordinary layman could make up a pretty good list of his own, some of the more common or garden variety targets can be mentioned without breaking any confidences or endangering the state of the Union.
General Intelligence would include such items as Japanese naval war plans, war diaries, and battle reports; budget estimates and annual construction figures; codes and ciphers; hydrographic and meteorological information; personnel figures and training programs.
Bureau of Ships was naturally interested in the characteristics of Japanese naval vessels in service or under construction; submarines; mine detectors and mine sweeping gear; electrical equipment; and ordinary things like ship’s-bottom paints.
Bureau of Ordnance wanted information about torpedoes and their aerial counterpart, guided missiles; mines and depth charges; rockets, bombs, ammunition, armor, too, and the big naval guns.
Bureau of Aeronautics inquired about new designs of aircraft; new types of engines; progress in jet propulsion; propeller research; de-icing equipment; ground servicing equipment; parachutes, flight clothing, and photographic materials.
Bureau of Medicine and Surgery was especially interested in data relative to life in the jungle and on sea islands, particularly that apropos diet, malaria control, insect repellents, etc.; infection of Naval personnel with tuberculosis (in view of Japan’s high T.B. rate); preventive medicine, neuropsychiatry, and rehabilitation. A special target of considerable interest at the time involved the medical effects of atomic bombing.
Electronics Targets were set up as a separate division, in view of the importance of this equipment in modern naval warfare. Information was desired about all kinds of radar and radar countermeasures; direction finders and navigational aids; electron tubes, antennas, insulation products; and many other subjects, all very technical.
Miscellaneous Targets comprised another division and included optics, special testing instruments, aerology, camouflage; fungus and anti-fungus data; synthetic lubricants and fuels, in which field the Japanese had done some very interesting work.
A bare glance at these widely divergent subjects and their highly technical and theoretical nature makes it abundantly clear why the Mission was staffed with officers, both regular Navy and Reserve, who were outstanding specialists in their respective fields. Many were former college instructors. Investigation, experiment, and analysis of construction and operation were for these men an open book; experience provided them with instant judgment as to the value or worthlessness of a material or design. But an ordinary individual would have been lost as a landlubber on this sea of science.
As early as September 15, 1945, copies of “Intelligence Targets—Japan’’ were received by NavTechJap and distributed to the officers concerned. This advanced planning crystallized the objectives of the Mission and permitted it to move at once into the field with specific purposes. A target is usually understood to mean a definite object in a specific place, but NavTechJap applied a slightly broader definition. A target was interpreted as a technical “subject” regardless of where activities pertaining to it might be located within the Empire. Every piece of equipment of the same type obviously would not be investigated, but the original and all subsequent modifications were covered. This method resulted in a comprehensive report on the development and use of the entire subject, and not just one unit or phase of it.
Only a few of the engineering and medical members of NavTechJap could speak Japanese. To undertake investigations in a foreign country without knowledge of the language would be like trying to scale a high wall without a ladder or rope. Navy planning had met this problem in advance, and language officers were made available, numbering approximately 80 at the peak of the investigations. Many of them had been teachers of language in high schools and colleges before their commissioning in the Naval Reserve. They had then been given six months to a year of intensive training in Japanese. This is an extremely difficult language, and their instruction, of course, had to cover not only social conversation but technical terms used in Navy work, in electrical engineering, chemistry, metallurgy, and so on. It was a terribly stiff assignment, and one that was handled well indeed. These language officers probably will be given very little credit for their performance, but without their able contribution the Mission would have bogged down completely. Fortunately engineering drawings and blue prints speak a universal language, and when these were available, as was often the case, the discussions proceeded at high speed.
Another helpful guide for NavTechJap investigations, was the “Report on Scientific Intelligence Survey in Japan, November 1, 1945” (the so-called “Compton-Moreland Report”) summarizing the findings of a small group of scientists who, in September and October, 1945, made a quick survey of the Japanese organization for scientific research and development. In fact, members of that survey, before publication of their report, gave advance suggestion to NavTechJap concerning certain fields or devices meriting immediate detailed investigation.
With “Intelligence Targets—Japan” as a guide, technicians and specialists in a particular field were assigned one or more targets. The activities of the individual investigations were closely supervised and coordinated by the section heads. As requested, key Japanese naval personnel and scientists were produced by the Japanese Liaison Office for interview and interrogation. In nearly all instances one or more of the language officers assigned to NavTechJap were present at these interviews to interpret both questions and answers. Visits were then made to locations where equipment and documents could be found. When deemed advisable, documents and samples of the equipment were seized and sent to one of the four NavTechJap collection centers which had been established at Sasebo, Yokosuka, Kure, and Kobe, where they were prepared for shipment to the United States.
After completion of the field work, the investigators returned to Tokyo where a complete report was first written in longhand. A staff of editors processed each report to determine its completeness and acceptability. The head of the cognizant Technical Department section reviewed the report for technical and engineering accuracy. No officer or technician was permitted to return to the United States until his report had been edited and accepted. Once accepted, the report was typed by the Japanese personnel in the Progress and Reports Section and made ready for shipment to the printer.
In many instances it was necessary to do more than simply investigate the material on hand. For example, a new model, 20-cylinder diesel engine was about fifty percent completed when Japan surrendered and all construction and development of war material stopped. The engine showed promising possibilities. The originating Japanese engineers and scientists were located and brought back to complete its construction, at the expense of the Japanese government. Upon completion, tests were run under NavTechJap supervision, to determine its performance.
The search for data and equipment on Japanese petroleum research seemed hopeless, until the remains of a laboratory were discovered at Ofuna. Most of the documents, data, etc., were said to have been destroyed, but enough remained to indicate that a sizeable establishment was once in operation there. Again the Japanese engineers, draftsmen, scientists, and research men formerly employed in the laboratory were assembled to duplicate plans, drawings, and experimental data which had been developed. Strangely enough, the Japanese scientists took considerable pride in accomplishing this work to demonstrate the extent of their advancement. The net result was a complete disclosure of Japan’s petroleum research.
By early February, 1946, reports in rough form were being submitted in volume. The means for completing and printing reports were not available in Japan, and CinPac made available the facilities of the Joint Intelligence!Center, Pacific Ocean Area, to the Mission for that purpose. JICPOA was well-established in Pearl Harbor in a separate building with trained personnel and modern equipment for typing, drafting, laying- out, and printing reports. The Progress and Reports Section was, therefore, moved by plane to Pearl Harbor on February 22, 1946. Upon completion of technical investigations, several weeks later, all activity of the Mission in Japan was terminated, and on March 11, 1946, the remaining personnel left the Empire and established headquarters in the JICPOA Building in Pearl Harbor. This arrangement permitted close cooperation, eliminated delays, and provided the highest possible security.
Editorial work was highly important. Since there were to be nearly two hundred separate reports, uniformity in arrangement was desirable. No effort was made to standardize the author’s style, though clarity of expression, accuracy of statements and figures, and adequate cross-referencing were necessary if the reports were to be of value. A proper segregation of descriptive matter and tabular statistics was sought, and much material placed at the end of the reports as appendices or enclosures, to avoid cluttering up the text. A summary was provided at the beginning of each report to give a quick picture to the reader not interested in detailed descriptions and figures. References were given to other NavTechJap reports on similar or related subjects or to those prepared by other activities.
NavTechJap and JICPOA worked so closely on the production of reports that the problems of one were the direct concern of the other. Difficulty in obtaining an adequate number of typists was matched by the need of capable layout personnel, and the demand for draftsmen was perhaps the hardest of all to solve. About May 1, for instance, when all possible sail was being hoisted to complete the project, NavTechJap had 10 draftsmen on this work; JICPOA furnished 5; Naval Shipyard, Pearl Harbor supplied 25; the 30th Engineer Topographical Battalion at Schofield, 6; Naval Shipyard, Mare Island, 35; and Naval Shipyard, San Francisco, 15.
All naval activities by this time had common problems resulting from the loss of highpoint, trained personnel and the demobilization of the Naval Reserve. But the work of the draftsman, photographer, printer required highly specialized skill which made replacement by inexperienced personnel (even when available), a very slow procedure. Consequently the small group of qualified personnel worked under extreme and unceasing pressure. Especial commendation is due JICPOA whose resourcefulness, untiring effort, and admirable “know-how” contributed so much to the success of the concluding phase of this Mission.
It is for others to evaluate the results of the many investigations undertaken by NavTechJap. Some targets were of interest because of new, unique, or superior design by the Japanese. Other targets produced seemingly negative results which nevertheless have positive value from knowing that another nation has verified our research and conclusions, or has tried methods new to us yet which failed of accomplishment.
NavTechJap investigators, unarmed and often alone, visited scores of places in Japan, both urban and rural, and never once were molested or threatened. Usually the American was ignored, little curiosity being displayed by Japanese adults. When the Japanese were asked for information, friendliness and willing cooperation were the general rule.
Of considerable interest was the observation that the Japanese Army and Navy both deliberately spurned the Japanese scientist, whose knowledge, laboratories, and research equipment might have contributed so much toward a more successful prosecution of the war by the Japanese. The scientist recognized this and felt deeply injured over the lack of confidence in his ability and his loyalty. Little organized research was carried on during the war outside of the Army and Navy. A corollary to this is the fact that by such policy Japan failed, in general, to realize those tremendous and permanent scientific advances that the modern nation gains from huge wartime expenditures for research.
The common concept that the Japanese lack originality and are merely an imitative people is in need of qualification. They entered the fields of science and mechanical industry only a comparatively few years ago. The sensible thing was to engage in wholesale copying until they caught up with other countries. Had they proceeded independently in scientific research and discovery, they would always have been fifty years behind. The Japanese may be especially adept at copying, but evidence of their originality and ingenuity is not lacking.
The Japanese received very little effective help from the Germans or the Italians. It is true that the Japanese 1-400 type submarines were equipped with Schnorkel, but it is understood that the Japanese saw a German submarine in Hong Kong and copied the Schnorkel features. A Japanese submarine crew was sent to Germany for training, but all hands were lost on the trip back. Some assistance was received from Germany pertaining to electronics, but Japan was still well behind us in the design of this equipment. Such information as the Japanese obtained was largely of a general rather than specific nature. The single important exception seems to have been the assistance given by Germany in the sonar field. Some of the Japanese equipment was almost an exact copy of captured British equipment.
At the time of the Pearl Harbor attack, Japan had a strong and well equipped navy, with ships that were of good design and rugged construction. Three of them, the battleships Yamato and Musashi, and the aircraft carrier Shinano, were the largest, and in many respects, the most powerful warships in the world. The Yamato and the Musashi had standard displacement of 63,000 tons each (when fully loaded, 73,000 tons) and a speed of 28 knots. Their main battery, consisting of nine 46cm. (18.1-inch) guns, had a maximum range of 45,000 yards. This is noteworthy in itself, since they were the largest naval guns in the world.
To match this, the largest United States battleships were the North Carolina and Washington, of 35,000 tons standard displacement, 28 knots speed, and main battery of nine 16-inch guns.
During the latter part of the war, surface ship production was largely abandoned by the Japanese in favor of submarine production, and during 1944 they brought out the 1-400 class—three huge submarines whose primary mission undoubtedly was the bombing of the Panama Canal and cities on the west coast of the United States. They had a displacement of 5,550 tons each, a length of 400 feet, a maximum speed of 19.7 knots surfaced and 7 submerged, and cruising range of 34,000 miles at 16 knots. Eight torpedo tubes and one 5.5-inch deck gun comprised the armament. In addition, in a hangar tube (11.6 ft. diameter) on the main deck, each submarine carried three bombing planes, each weighing about four tons, capable of 290 knots speed, and carrying a bomb of 0.8 tons or one 18-inch airplane torpedo.
By comparison, our largest submarine was the Nautilus, with a displacement of 2,730 tons, a length of 371 feet, a speed of 17 knots surfaced and 8.5 submerged, and a cruising range of 15,000 miles. The armament consisted of eight tubes for 21-inch torpedoes, and two 5-inch guns which were later replaced by 3-inch.
The Japanese developed very successfully torpedoes of three different types, using pure oxygen, air, and electricity for propulsion. There was nothing unusual about the 18- inch, air-driven torpedo, but the 21-inch electric type, with a range of 7,500 yards at 30 knots, was an effective weapon because it left no wake and was easy to manufacture; hence it was used extensively.
In time of war, persons of every nationality show unlimited courage and self-sacrifice, but never before was the willingness of the individual soldier to destroy himself so incorporated into the wartime policy of a nation. When Japan was forced to change from offensive to defensive warfare, she realized it would cost the lives of many brave men, but coolly and efficiently she devised plans and equipment which would take numerous enemy lives in exchange for each native son.
The best known of these implements of self-destruction was the Kamikaze plane, or dive bomber, which was considered not so much a projectile carrier as the projectile itself, with a human being as part of its steering and control mechanism. The men who volunteered for this one-way ride were a select group of Japan’s best pilots, and there were always more volunteers than planes.
The Baka Bomb and its human control was a variation of the same idea of death in and from the air. This was a small jet plane or glider, with a pilot locked in, along with a heavy load of high explosive. It was carried under the fuselage of a larger plane which launched it a few miles from its target.
On the surface of the water, it took the form of Shinyo, a small special attack boat which utilized the explosive charge in its bow by ramming the side of the intended victim. These motor boats were collected in special attack basins along the coast or were carried on mother ships. Such suicide craft were manned by middle school boys of 15 and 16 years of age. It is reported that an ample supply of volunteer pilots was obtained because of special privileges, early responsibility, fast promotion, and the promise of a posthumous monetary award to the volunteer’s parents.
Underwater opportunities for destruction stimulated the Japanese imagination. The Kaiten (“Great Undertaking”) was a one- man submarine which was substantially an altered torpedo having human control, and with additional fuel capacity inserted between the torpedo warhead and the torpedo engine. Six Kaiten were carried on the decks of I-type submarines and connected by tubes through which the pilot could enter the torpedo and start on his journey without the submarine having to surface. These midget or suicide subs were manned by young volunteers of 18 to 20 years, attracted by much the same inducements offered the Shinyo pilots. The Japanese claimed great success in the encounters between Kaiten and enemy shipping.
The Japanese also had amphibious tanks 35 feet long, that rode “piggy back” on submarines. In preparation for an attack, the submarine would surface, and, after the tank had drained, it would be boarded by a crew of one officer and six men and a landing party of 35 men. The tank would then be driven off the sub, or the latter would submerge, leaving the water-borne tank ready to proceed under her own power. When the Nipponese strategy turned defensive in 1944, these sea-going tanks were modified to include torpedo cradles. Upon reaching an objective, both torpedoes would be released at short range. No attempt to return ashore for re-loading would have been made, as the expendable tank would have simply been scuttled on the spot, and the brave but hapless crew would join their honorable ancestors. (These mechanical oddities were never known to have been used operationally, although about 100 were built.)
Still another, though less well-known suicide group, was the Fukuryu, or “Crouching Dragons.” Had the war reached the stage of repelling an amphibious landing on the shores of Honshu, the Fukuryu were prepared and equipped to walk underwater and ram an explosive bomb against the hull of an enemy landing craft. These “underwater kamikazes” wore diving suits equipped with two oxygen tanks, submarine-type air cleaning devices, and tubes for liquid food, and could operate effectively in water 50 feet deep; they could walk underwater more than a mile an hour, and could stay underwater for ten hours. At the war’s end, 4,000 Fukuryus were at the Yokosuka Naval Base, of whom 1,200 were fully trained.
Loss of much of her shipping capacity and the resulting fuel and food shortage caused Japan to give consideration to suggestions by her oceanographers that ocean currents be utilized for transportation of necessities. Since 90 per cent of the drift bottles set adrift in the Japanese Sea off the east coast of Korea reached the northern part of Honshu, it seemed feasible to use the Kuroshio (Japan Current) for the transportation of soya beans from Manchuria and other goods from Formosa, Nansei Shoto, etc., to Japan proper. A small wooden ship of 200 tons was successfully floated from Fusan to Honshu. Then plans were made for floating metal drums which would drift below the surface, but some in every lot would be equipped with radios and at intervals would rise and be contacted by land stations in order that their movements could be traced. Loss of the Philippines, meantime, prevented carrying out the plan.
Japan was far behind us in the field of electronics, but her experiments with a “Death Ray” may have the unique outcome of saving countless lives threatened by tuberculosis. These experiments showed a pronounced effect on the lungs of the animals tested, and further research was contemplated toward a possible cure for tuberculosis. It was noticed that higher frequencies affected the brain. The investigators realized that heat was an evident factor, but were sure that frequency was important also. The frequency characteristic could be associated with the resonance dimensions of the head and body respectively. It is quite possible that Japanese or American investigators may develop treatment for tuberculosis and for certain brain disorders that will have great therapeutic value. A mass chest X-ray program for the diagnosis of tuberculosis was interrupted by the war, but Japan was using an “immunization” technique that should be further investigated.
The Japanese medical officers observed that most cases of night-blindness occurred with pilots having liver trouble and whose secretion of the bile was not normal. Acting on this hint, they developed a preparation named “Migozai” whose ingredients stimulate the secretion of the bile and the absorption of Vitamin A, so necessary for the retina of the eye. The vision of the dark-adapted eye when taking this preparation improved from 1§ to 2 times. This means that, looking at the same object, the eye can see it from twice the distance.
More notable, and certainly more far reaching, is the discovery of two drugs by Japanese who were searching for some therapeutic agent resembling chlorophyll, with its power of converting sunlight into energy. These were derived from neocyaine and named Koha and Shiko (meaning Rainbow Wave and Violet Light). The drugs improve general body resistance and stimulate regeneration of tissue. The Japanese have demonstrated remarkable results with these when used in leprosy cases. Burns and frostbite responded with gratifying acceleration, while benzine burns and boiling water burns, especially, showed quick improvement.
Of considerable interest is an unusual type of hangar construction that the Japanese had developed. It was called the “Diamond Truss,” from the diamond-shaped pattern formed by the intersecting arches. It is in reality a hangar made of a series of intersecting skew arches. In this novel design, the skewed arches form the longitudinal bracing of the structure in addition to taking the regular loading. The design resulted in a tremendous saving of steel. At first glance it would appear that the cost of fabrication of such an unorthodox structure would be prohibitive, but actually no bent plates or structural shapes were necessary, and standardization on the size of hangars kept the steel detailing to a minimum. The entire structural frame is made up of plates and angles. To avoid complicated framing at the intersections of the arches, the top and bottom chords of the arches were cut and framed into gusset plates. This type of construction might well receive consideration by our architects and builders for any structure where large roofing areas are involved, such as hangars, garages, factory and mill buildings, armories, and gymnasia.
Petroleum was the “Achilles Heel” in the Japanese armor, and her lack of this precious fuel was the fundamental cause of her downfall. When the Japanese super-battleship Yamato made her suicidal sortie southwest of Kyushu in the waning months of the war, she was powered by edible refined soya bean oil. U.S. Navy planes sank the soy bean-burning warship April 7, 1945, when she was intercepted enroute to attack American shipping at Okinawa.
Lack of oil resources kept scores of Nipponese ships lying immobile in Kure and other ports, and many of her battleships and cruisers were sitting-duck targets, easily sunk by bombs and torpedoes dropped by our airmen.
Japan’s efforts to find substitute fuels were frantic (and to a limited extent effective), but entirely inadequate. Until the beginning of the war, the Japanese Navy’s chief source of diesel and bunker fuel was imports from California. This stockpile was exhausted in 1942, and cracked residues from Sumatra and Borneo crudes were then utilized as bunker fuels. In 1944, due to Japanese tanker losses to U. S. submarines, research and practical testing were undertaken on both diesel and boiler fuels to develop substitutes. By the spring of 1945 aircraft carriers were utilized as tankers to bring motor gasoline from Singapore to be used as charging stock in the manufacture of even more desperately needed aviation fuel.
Satisfactory diesel fuels were produced from coconut oil, hydro cracked; pressed copra oil; esterified copra oil; and soya bean oil. Pine root oil was used, too, but had a tendency to leave gummy deposits in the engine. A determined effort was made to develop an industry for converting coal into oil, but the results were comparatively insignificant. As a matter of fact, the outputs of oil from shale at Fushan, until 1944, exceeded the combined output from all coal conversion processes.
During the last year of the war the Japanese had considerable success with a program for producing alcohol and using alcoholic aviation fuels. For instance they were able to produce one pound of ethyl alcohol from the fermentation of eleven pounds of sweet potatoes. This in turn necessitated vital decisions about which varieties of potatoes were best for food and which best for fuel, and how the two should be apportioned to keep the nation alive to fight.
By the spring of 1944, the supply of cane sugar and molasses from Formosa, Java, and the Philippines was decreasing and more emphasis was placed on Manchurian grain as a raw material source of ethyl alcohol. Finally, butanol plants were converted to the production of ethyl alcohol. Thus the Japanese were converting rubber into gasoline for war purposes, while in America gasoline was being converted into rubber.
Such were some of the highlights reported by the Mission. In all, its investigations resulted in the preparation and printing of 186 target reports; 3,500 Japanese documents and 15,000 pieces of equipment were seized and shipped to the United States for further examination. (The largest items were two 18.1-inch guns shipped from Kure, each 75 feet long and weighing 180 tons.) The members of the Mission make no claims, but surely few Japanese naval secrets escaped the penetrating probe and searching spot light of NavTechJap.