For over 200 years, beginning in 1639, the frontiers of Japan were closed to the world. So complete was the ruling Tokugawa Shogunate’s desire for isolation that even the building of large seagoing vessels was prohibited in Japan. Then, in July 1853, Commodore Matthew C. Perry landed at Kurihama, some 5 miles from Yokosuka at the mouth of Tokyo Bay, with his squadron of “black ships.” Perry pressed for the opening of ports from which American ships could take on coal and supplies. Yielding to pressures from both within and beyond its borders, Japan soon ended its policy of isolation.
With its “closed door” policy terminated, the Shogunate government purchased several ships from foreign powers, and the need for a suitable ship repair facility developed. Under the guidance of French government officials, a shipyard site was selected at Yokosuka, a fishing village south of Yokohama, in part due to the area’s resemblance to the French port of Toulon. In September 1865, the Yokosuka Iron Works was established, with about 300 workers in its employ.
1965, then, marks Yokosuka’s 100th active year; the yard has been witness to the development of the modern warship and to the creation of much of the Imperial Japanese Fleet. Today, Fleet Activities, Yokosuka, serves as the home base of the U. S. Navy’s far-flung Seventh Fleet.
Construction of the shipyard was supervised by Leonce Verny, a French naval architect, and his staff of French engineers. The keel of the first ship to be built at the yard was laid in 1866, and in 1872, Yokosuka’s first drydock, of some 4.000 tons, was completed.
The Seiki, the first significant Yokosuka-built warship, was launched in 1875. Designed by Verny, and displacing about 900 tons, she was a gunboat of wooden construction. That same year, management of the yard was transferred from the French to the Japanese. By 1876, the yard’s staff had grown to some 1,800 men.
In 1904, five Holland-type submarines were prefabricated in secrecy by a private company in the United Slates and shipped to Japan. Assembled at Yokosuka in 1905, they formed the genesis of Japan’s underseas fleet.
For a time, most major Japanese naval vessels were purchased from foreign builders, but soon after the turn of the century, Japanese yards were producing men-of-war second to none. The armored cruiser Kurama, launched at Yokosuka in 1907, mounted four 12-inch, eight 8-inch, and H k.7-inch guns. The Satsuma, launched at Yokosuka a year earlier, was the world’s largest battleship then afloat, with a main battery of four 12-inch guns in two turrets, and 12 10-inchers in six turrets.
In May 1920, the battleship Mutsu, was launched at Yokosuka. 700 feet in length, and carrying eight 16-inch guns, the Mutsu and her sister ship Nagato were the first in the world to mount batteries of that size.
On 1 September 1923, the great Kanto earthquake caused severe damage throughout the Tokyo area. At the Imperial Navy Yard in Yokosuka, more than 100 of the yard’s several thousand workers were killed. The harbor bottom was raised several feet, submarines in a drydock turned over, buildings were destroyed, and about 70,000 tons of vital fuel oil were lost from ruptured storage tanks.
At that time, the partially completed cruiser Amagi was on the ways at Yokosuka, being converted into an aircraft carrier. The Amagi was so severely damaged by the earthquake that she was scrapped. In her place the battleship Kaga, which had been scheduled for scrapping under the Washington Naval Treaty, was converted into an aircraft carrier. The 28,100-ton Kaga was one of the six carriers in the Hawaii Operation in December 1941. She was lost in the Battle of Midway.
During World War II, activities at the Imperial Navy Shipyard reached their peak, with the yard covering 280 acres and employing over 100,000 workers. Four aircraft carriers and more than two dozen destroyers and submarines were completed at Yokosuka during the war.
The Yokosuka Navy Yard was the target for one of the 16 Army Air Force B-25s launched from the USS Hornet (CV-8), in the Halsey-Doolittle raid of 18 April 1942. The B-25’s three 500-pound demolition bombs and one incendiary cluster damaged several workshops, a dockside crane, and the submarine lender Tagei, in drydock.
When damaged by the B-25 attack, the Tagei was in the process of being rebuilt into an aircraft carrier, provision having been made for such conversion in her original design. Renamed the Ryuho, she was a participant in the Battle of the Philippine Sea. Of the 11 aircraft carriers completed at Yokosuka, only the Ryuho and the old Hosho, Japan’s first aircraft carrier, survived the war. Both were subsequently scrapped.
No known photograph exists of the 68,000-ton Shinano, largest ship ever constructed at Yokosuka. Laid down in great secrecy, she was designed as a sister to the super-battleships Yamato and Musashi. However, midway in construction, she was redesigned as an aircraft carrier, in part due to the loss of four Japanese carriers at the Battle of Midway. The Shinano was sunk by the submarine USS Archerfish (SS-311) on 29 November 1944, only ten days after she had been commissioned.)
A navigation and a gunnery school were among the Imperial Navy training facilities at Yokosuka. A two-gun turret, removed from a ship, was used for training purposes at the gunnery school.
Through most of the war the Yokosuka naval facilities were left untouched by Allied forces. However, on 18 July 1945, in one of their concluding sweeps through Japanese waters, U.S. and British carrier aircraft from Task Force 38 conducted raids on the shipyard and harbor areas. The attacking aircraft sank a destroyer and a submarine, damaged the battleship Nagato, and destroyed several smaller vessels.
On 30 August 1945, Vice Admiral M. Totsuka, Commander of the Yokosuka Naval Base, surrendered his command to the Allies, and it was peacefully occupied by approximately 10,000 U. S. and British Marines and naval personnel. During its dynamic years of service to the Imperial navy, the shipyard had constructed over 100 warships and repaired or overhauled innumerable others.
50 five-man midget submarines had been built at Yokosuka when the war ended. With a diesel generator, electric motor, and batteries, the subs had a surface range of about 1,000 miles. More than 200 smaller gasoline-powered two-man submarines had also been constructed at the yard, in preparation for the Allied invasion of the Japanese home islands.
The wartime naval complex at Yokosuka extended for several miles along Tokyo Bay, and, in addition to the shipyard, included a gun factory, ordnance depot, supply depot, fuel storage facility, seaplane base, and naval air station.
Moored at Yokosuka because of the acute shortage of fuel oil, the 700-foot Nagato was the only Japanese battleship still afloat at the end of the war. Completed at Kure in 1920, she fought in the Battles of the Philippine Sea, Leyte Gulf, and Samar. A target ship in Operation Crossroads at Bikini in July 1946, the Nagato sank a few days after the "Baker” nuclear underwater explosion.
Following World War II, much of the machinery of the Imperial Navy Yard was destroyed or shipped abroad as reparations payments. However, to meet the repair needs of the Allied occupation forces, the U. S. Naval Ship Repair Facility, Yokosuka, was established in April 1947, with a staff of 75 U. S. naval personnel and 576 Japanese engineers and workers. Occupying 72 acres, or approximately one quarter of the former yard area, the facility utilized the original drydocks, piers, and cranes, with many new improvements being made in the buildings and shops.
As the major naval repair facility in the Far East, the Yokosuka yard assumed a vital role in Seventh Fleet operations during the Korean War. To meet the increased demands for ship overhauls and repairs, employment at the yard increased to several thousand workers. Among the many Seventh Fleet units in Yokosuka during the war were the USS Missouri (BB-63) and the USS New Jersey (BB-62), center, and the USS Boxer (CV-21), below.
In May 1961 the Card, a civilian-manned aircraft transport, was damaged by an underwater explosion after offloading aircraft at Saigon, South Vietnam. Refloated and given emergency repairs at Subic Bay, the Card was towed to Yokosuka for complete restoration. In addition to replacement of the damaged hull sections, blast and water damaged engines and reduction gears had to be repaired. The Card left the yard in December 1961, a month ahead of schedule, and at a savings of over $500,000.
Post-Korean War cutbacks and regular retirements have gradually reduced the manning level of Japanese workers at the Ship Repair Facility to around 2000+ men. Provided through a master labor contract between the U. S. and Japanese governments, their wage scale and classification system are patterned after the Japanese civil service. They work in 17 skilled trades, and their pride in their work and long length of service reflect the traditions of their forebears. In a group of recent retirees, over ten per cent had served in the shipyard for more than 15 years.
With 18 berths and six dry docks, the Ship Repair Facility can service an average of more than 600 ships per year, and most Seventh Fleet units put into the port at least once during their Western Pacific deployments. Nearly 100 ships go into drydock annually, over 2,000 having been drydocked at the facility since its establishment in 1947.
Fleet Activities, Yokosuka, which includes the Ship Repair Facility; Headquarters for the Commander, U. S. Naval Forces, Japan; Naval Supply Depot; Ordnance Facility; Marine Barracks; and Naval Hospital, is the largest U. S. Navy complex in the Far East. In all, more than 3,000 U. S. Navy, Marine and civilian personnel are stationed there, and over 6,000 Japanese employed. The Japanese Maritime Self-Defense Force also maintains a base at Yokosuka and makes use of the yard’s facilities. Backed with a tradition of 100 years of naval history, the Yokosuka naval facilities have a useful place in Japan’s economy and are a vital link in the Free World’s defenses.
