Imperial Japanese Navy - YAMATO class Battleship ==========================================================================




Yamato, lead ship of a class of two 65,000-ton (over 72,800-tons at full load) battleships, was built at Kure, Japan. She and her sister, Musashi were by far the largest battleships ever built, even exceeding in size and gun caliber (though not in weight of broadside) the U.S. Navy's abortive Montana class. Their nine 460mm (18.1-inch) main battery guns, which fired 1460kg (3200 pound) armor piercing shells, were the largest battleship guns ever to go to sea, and the two ships' scale of armor protection was also unsurpassed.

The Yamato class battleships were battleships of the Imperial Japanese Navy (IJN) constructed and used during World War II. Displacing 72,800 metric tons at full-load, the vessels of the class were also the largest, heaviest, and most heavily armed battleships ever constructed. The class carried the largest naval artillery ever fitted to a warship—460 mm (18.1 in) naval-guns, each of which could fire 2,998lb (1.36 tonnes) shells over 42 km. Two battleships of the class—Yamato and Musashi—were completed, while a third—the Shinano—was converted to an aircraft carrier midway through construction.

Only one of the three vessels would ever see active combat—the Yamato during the Battle off Samar. The Musashi would spend the majority of her life in the naval-bases at Brunei, Truk, and Kure, before being sunk during the Battle of Leyte Gulf. The Shinano was sunk in 1945 by the submarine USS Archerfish, and the Yamato was sunk in April 1945 during Operation Ten-Go

IJN Battleship Yamato, named after the ancient Japanese Yamato Province, was a battleship of the Imperial Japanese Navy during World War II, and flagship of the Japanese Combined Fleet. She was lead ship of her class. She and her sister ship the IJN Musashi were the largest, heaviest, and most powerful battleships ever constructed, displacing 72,800 tonnes at full load, and armed with nine 46 cm (18.1 inch) main guns.


Constructed from 1937-1940 and formally commissioned in 1941, the Yamato became the flagship of Admiral Isoroku Yamamoto in May 1942, first sailing as part of the Combined Fleet in the Battle of Midway in June 1942. The Yamato was subsequently involved in every major surface naval-battle (excluding the Guadalcanal Campaign) of the Pacific War . The Yamato was sunk in April 1945 during Operation Ten-Go.

The Yamato class was the absolute ultimate in Battleship design. Built in great secrecy, they mounted 18.1 inch main guns which were the largest guns ever to be installed on a ship. To meet the increasing threat from the air, massive anti aircraft armament was fitted all round.

The 18.1 inch ( 46 cm) calibre guns used on the Yamato were the most powerful guns ever installed onto a Battleship. The muzzle blast was known to knock people senseless and blow away their clothes if they stood too close when they were fired ! The Japanese designated these guns as "Type 94 40 cm (15.9 inches)" in order to keep their actual calibre a secret.

The six foot 3,200 pound projectiles were the ammunition for the largest guns ever to go to sea. Aboard the Japanese Imperial Navy battleships Yamato and Musashi, these projectiles could be hurled more than 25 miles at 40 second intervals by 18 inch guns. The 71,000 ton Yamato, the largest battleship in the world, was completed December 1941. Her sister ship, Musashi, was completed eight months later.

Design of a super battleship class of warships was initiated by Japan's Naval General Staff in 1934, even though at the time the country was a signatory of the Washington Naval Treaty. That treaty, as extended by the London Naval Treaty of 1930, forbade signatories to build new battleships.

The design was in response to the perceived numerical superiority of the American battlefleet, which Japan anticipated as a likely future adversary. The intended super battleship, as requested by Japan's Navy's leaders, was intended to outrange and outgun any battleship in existence or that might be built within the next ten years. The 18-inch guns originally planned for the cancelled Number 13 class battleships were directed to be incorporated into the design, along with heavier than usual anti-aircraft (AA) armament and a capability to steam at 30 knots.

The proposed design, however, was too advanced for Japan's current technology and engineering capabilities, so the requirements were modified to a vessel with a top speed of 27 knots.

The design was for a 62,000 ton ship equipped with nine 18-inch, 12 6-inch, twelve 5-inch AA, 24 25mm AA, and 16 13mm guns. The ship was powered by two shaft turbines of 75,000 HP and two shaft diesels of 60,000 HP. The diesels were 2-cycle double-acting engines of the same type as mounted in the submarine tender Taigei. Although the diesel engines were slightly heavier than equivalent turbine engines, their fuel consumption was much less.

Two months after accepting the design, a serious defect was discovered in Taigei's diesel engines. Since the battleship's engine rooms as designed would be covered with 8-inch armor, this would prevent future removal of the engines to repair any serious problems. Thus, the designers were ordered to replace the diesel engines with proven turbine engines. With the new engines, the battleship's total HP increased from 135,000 to 150,000. The change in engines increased the weight of the vessel to 68,000 tons. This final design was accepted in March 1937.

Several features were incorporated into the design to help increase the battleship's top speed. The Number One turret was well depressed into the hull to decrease wind resistance. The bridge and superstructure was also designed to provide less wind resistance. To reduce wave resistance and to partly offset the effects of the severe breadth/length ratio, a large bulbous bow was included.


Construction of the Yamato class began after the Japanese withdrew from the Washington Naval Treaty at the Second London Conference of 1936. Yamato was built in intense secrecy at a specially prepared dock to hide her construction at Kure Naval Dockyards beginning on 4 November 1937. She was launched on 8 August 1940 and commissioned on 16 December 1941.

Originally, four ships of this class were planned. Yamato and Musashi were completed as designed. The third, Shinano, was converted to an aircraft carrier during construction after the defeat at the Battle of Midway. The un-named "Hull Number 111" was scrapped in 1943 when roughly 30% complete.

The class was designed to be superior to any ship that the United States or Great Britain was likely to produce. Her 460 mm ( 18 in) main guns were selected over the usual 406 mm (16 in) ones because the width of the Panama Canal would make it impractical for the U.S. Navy to construct a battleship with the same caliber guns without severe design restrictions or inadequate defensive arrangement. To further confuse the intelligence agencies of other countries, Yamato's main guns were officially named 40.6 cm Special, and civilians were never notified of the true nature of the guns. At the Kure Navy Yard, the construction dock was deepened, the gantry crane capacity was increased to 100 tonnes, and part of the dock was roofed over to prevent observation of the work. Many low-level designers and even senior officers were not informed of the true dimensions of the battleship until after the war. When the ship was launched, there was no formal commissioning ceremony or fanfare.

Yamato was the flagship of Admiral Isoroku Yamamoto from 12 February 1942, replacing Nagato. She sailed with Nagato, Mutsu, Hosho, Sendai, nine destroyers, and four auxiliary ships as Yamamoto's Main Body during the attempted invasion of Midway Atoll in June 1942, but took no active part in the Battle of Midway. After the loss of four aircraft carriers, Admiral Yamamoto had initially planned to send his battleships to shell Midway Island, but ultimately decided against it since they would have no air cover . She remained the flagship for 364 days until 11 February 1943, when the flag was transferred to her sister ship Musashi.

From 29 August 1942 to 8 May 1943, she spent all of her time at Truk, being underway for only one day during this entire time. In May 1943, she returned to Kure, where the two wing 155 mm turrets were removed and replaced by 25 mm machine guns, and Type-22 surface search radars were added. She returned to Truk on 25 December 1943. On the way there, she was damaged by a torpedo from the submarine USS Skate, and was not fully repaired until April 1944. During these repairs, additional 127 mm anti-aircraft guns were installed in the place of the 155 mm turrets removed in May, and her anti-aircraft battery was considerably increased.

She joined the fleet in the Battle of the Philippine Sea in June 1944. This saw the end of the IJN's carriers as an effective fighting force, but also forced the Japanese to refocus priority on their battleships.

In October, she participated in the Battle of Leyte Gulf, during which she first fired her main guns at enemy aircraft and surface ships. On 20 October 1944, U.S. Forces landed on the Island of Leyte, the first of the Japanese-held Philippine Islands to be invaded. In response, the Japanese Navy activated the complex "Sho-Go" Operation, in which several different surface and air forces would converge on the Philippines to try and drive off the Americans. During the initial air attack, she received two bomb hits from aircraft which did little damage. However, her sister, Musashi, bore the brunt of the US carrier aircraft attacks. In a demonstration of the Yamato-class battleship's expected resilience to attack, Musashi finally sank only after she received a staggering number of hits (the exact number is still debated to this day: American sources report 10 torpedo hits to her port side, 9 to her starboard side, 17 bomb hits, and 18 near misses, while Japanese sources report 11 total torpedo hits, 10 bomb hits, and 6 near misses). Yamato and her compatriots later sank an escort carrier and some escort vessels at Samar; Yamato herself was credited by her Pete spotter plane as having hit the escort carrier USS Gambier Bay.

During the morning of 25 October, while off Samar, Kurita's Center Force encountered a U.S. Navy escort aircraft carrier task group. In a long running battle, in which Yamato fired her big guns at enemy ships for the only time in her career, one U.S. carrier and three destroyers were sunk. Fiercely opposed by the escort carriers' planes and the destroyers' guns and torpedoes, Vice Admiral Kurita lost three heavy cruisers, and his nerve. Though the way was almost clear to move onward to Leyte Gulf, where a climactic battleship gunnery duel would have certainly resulted, he ordered his force to withdraw and return to Brunei Bay. That ended Yamato's participation in the last great naval battle of World War II, and marked the end of the Japanese Fleet as a major threat to Allied offensive operations in the Western Pacific.

She returned home in November and her anti-aircraft capability was again upgraded over the winter. She was attacked in the Inland Sea on 19 March 1945 by carrier aircraft from Task Force 58 as they attacked Kure, but suffered little damage.

On 6 April 1945, Yamato was sent on a suicidal mission (operation Ten-Go) against more than 1000 US ships off Okinawa. US carrier-based aircraft sank her before she was able to reach her intended targets.

Soon after Okinawa was invaded on 1 April 1945, the Japanese implemented a desperate effort to destroy the fleet supporting the landings. Designated "Ten-Go", this operation largely consisted of massed "Kamikaze" suicide plane attacks. However, the battleship Yamato, largest surviving ship of the Japanese Navy, was also to play a role, steaming down from the home islands to blast invasion shipping off Okinawa's western coast. This mission was also understood to be suicidal, and only enough fuel was provided for a one-way cruise.

As the United States 10th Army began their invasion of Okinawa on 1 April, Yamato was moving south towards the island on what was to be her final mission. Code-named Operation Ten-Go and commanded by Admiral Seiichi Ito, Yamato—escorted by the Light Cruiser Yahagi and eight destroyers—was to beach herself on the west side of Okinawa. Having become an unsinkable gun emplacement, Yamato was to then shell American forces landing on the island. Yamato and her escorts only carried enough fuel to reach Okinawa, as Japanese fuel-supplies were too low to allow for a return voyage.

All of the officers and crew assumed that the voyage would be her last. Yamato had no air cover for her final mission, nor did she have many escorts. Even though the battleship was heavily armored, the crew were fortunate that they were covered by a rain squall which deterred air sorties for the first part of the journey. On her final evening, as U.S. carrier planes were expected to attack the next morning after the squalls lifted, the officers allowed or even ordered the crew to indulge in sake, a common ritual that kamikaze pilots would take before their final mission.

At about 0830 hours on 7 April 1945, United States fighter planes were launched to pinpoint the Japanese task force. By 1000 hours, Yamato's radar picked up the U.S. planes and a state of battle readiness was commanded. Within seven minutes all doors, hatches and ventilators were closed, and battle stations were fully manned.

The Yamato group was provided with no air support, so the U.S. planes were opposed only by generally ineffective anti-aircraft gun fire.

Strafing attacks by the US warplanes would decimate many of the AA gun crews, reducing the battleship's ability to fend off the attacking US aircraft.

The dives began at 20,000 ft directly over the Yamato, bearing from stern to bow. Bombs were released at an altitude of less than about 500 m (1,500 ft). The dives were made as close to a 90-degree angle as possible to avoid most anti-aircraft guns.

The torpedo plane pilots were ordered to aim for the parts of the Yamato's hull unprotected by her torpedo defense system: the bow and stern. They were also ordered to attack her on one side only, so that their target would capsize more easily since counter-flooding would become more difficult. Within minutes of the torpedo attacks, the Yamato suffered three torpedo hits to her port side and began listing.

Over the next two hours, two more attacks would be launched, pounding the Yamato with torpedoes and bombs. Attempts at counter-flooding failed, and shortly after 1400 hours, the commanding officer gave the word to prepare to abandon ship. As the ship listed beyond a 90° angle and began sinking bow first, a gigantic explosion of the stern ammunition magazines tore the ship in two parts. The huge mushroom of fire and smoke exploded almost four miles into the air and the fire was seen by sentries 125 miles away in Kagoshima prefecture on Kyushu, the southernmost of Japan's four main islands. Only 280 of the Yamato 2,778-man crew were rescued from the sinking ship. The end had come for the Yamato, foreshadowing the coming end of the Imperial Japanese Military. Only 10 aircraft and 12 airmen were lost in the attack on the Yamato.

Naval gunfire took no part in Yamato's demise. The sinking of the world's largest battleship by aircraft alone confirmed the lessons learned by the sinking of the Prince of Wales, Repulse, and Musashi: The battleship had been supplanted by the aircraft carrier as queen of the sea and the capital ship of any fleet.


The senior surviving bridge officer Mitsuru Yoshida claims that a fire alert for the magazine of the forward superfiring 155 mm guns was observed as the ship sank. This fire appears to have detonated the shell propellant stored as the ship rolled over, which in turn set off the magazine in Turret No. 2, resulting in the famous pictures of the actual explosion and subsequent smoke column photographed by US aircraft (and recorded as being seen in southern Japan, one hundred miles away).

A further large hole was found in the stern section, strongly suggesting that a third magazine explosion occurred, possibly the aft 155 mm gun magazine.

By far the largest Battleship of WW II. With a maximum displacement of 71659 tons, she was also the heaviest armed and armored of all battleships. This great ship was built in complete secrecy and it was not until very late in the war that it was found out how large and powerful she really was.

After the war, the great battleship became an object of intense fascination in Japan, as well as in foreign countries. Yamato's remains were located and examined in 1985 and again examined, more precisely, in 1999. The Japanese plan no further expeditions and are respecting the wreck as a burial site for the 2,498 men that went down with her. The ship was torn apart by a huge explosion forward of the aft 18-inch turret as she sank and the wreck is a tangled mess amidships. The fantail, with propellers, rudder and auxiliary rudder lies upside down in the mud. The forward hull, from the bow to the bridge area, lies on her starboard side, the number one 18-inch gun barbette is empty and half-filled with mud. The number two 18-inch gun turret is still mounted and traversed about 120 degrees to starboard with the gun barrels buried in the mud. About 30 meters north of the main hull, lies an 18-inch gun turret, upside down. About 70 meters south of the main hull, is a large section of hull, also upside down. The entire structure is slowly sinking into the mud. She lies in two main parts in some 1000 feet of water. Her bow portion, severed from the rest of the ship in the vicinity of the second main battery turret, is upright. The midships and stern section is upside down nearby, with a large hole in the lower starboard side close to the after magazines.

It appears to me that if you have a ship the size of the Yamato or even the Bismarck, it just presents itself as a big target, and one high on the enemies agenda as something to be removed from the field of play. Consequently these ships spent most of their short lives safely docked in harbor out of harms way, which surely was not the intention of having them in the first place.

The day and age of the Battleship is over, finished for good. The aircraft carrier as its replacement is a much more formidable weapon of war.

Ironically, the third hull of the five projected Yamato-class superbattleships was converted to a carrier while still under construction.


Shinano was laid down in June 1940 at Yokosuka Navy Yard, but construction was suspended in the summer of 1941 to free manpower and resources for approaching hostilities. After disastrous losses at the Battle of Midway, the decision was made to convert Shinano into an aircraft carrier.

The conversion process for Shinano placed a heavy emphasis on armor. For example, the flight deck was designed with 17,700 tons of steel—enough to withstand a 1,000-pound bomb. With a full-load displacement of almost 72,000 tons, it was the largest aircraft carrier ever built until the commissioning of the supercarrier USS Enterprise in 1961. Shinano was designed as a support carrier, using its extensive machine shops and large fuel capacity to service aircraft operating on other carriers. It would have had a very small air group of its own but a large number of unassigned aircraft to replace losses on other carriers.

The ship's very existence was kept a closely-guarded secret. A tall fence was erected on three sides of the graving dock, and those working on the conversion were confined to the yard compound. Serious punishment—up to and including death—awaited anyone who breathed a word about Japan's new carrier. As a result, Shinano was the only major warship built in the 20th century to have never been officially photographed during its construction.

Under these conditions, Shinano was launched on October 5, 1944 and formally named on October 8. She left the yard for builders' trials on November 11, 1944, and was commissioned on November 19.

American Naval Intelligence didn't even know Shinano existed when it left port, but had suspected there was a third Yamato-class battleship. Archer-Fish was initially given credit for sinking a 28,000-ton carrier. It wasn't until after the war that the Americans discovered that Archer-Fish had brought down a 72,000-ton leviathan.

To this day, Shinano is the biggest warship to have ever been sunk by a submarine.


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NB: The above text has been collected / excerpted / edited / mangled / tangled / re-compiled / etc ... from the following online sources :

IJN - YAMATO class Battle Ship - wikipedia article #1

IJN - YAMATO class Battle Ship - wikipedia article #2

IJN - YAMATO class Battle Ship - www.globalsecurity.org

IJN - YAMATO class Battle Ship - www.vincelewis.net

IJN - Super Battleships of Japan - www.ibiblio.org