Turtle ship

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Turtle ship
Model of a turtle ship
Korean spelling
Hangul : 거북선
Hanja : 龜 船
Revised Romanization : geobukseon
McCune-Reischauer : kŏbuksŏn
Type: Warship
Country of origin: Korea
Deployed by: Korean Navy
war Imjin war
First manufacture
Designed by: Admiral Yi Sun-sin , Lieutenant Na Dae-yong
Design year: 1591
First manufacture: March 27, 1592
Number: 3 to 5
Ship data
Width: 9 to 12 meters
Length: 30 to 37 meters
Crew: 80 rowers, 50 soldiers
Gun range: about 200 to 600 meters

The turtle ship, or geobukseon, was a Korean type of warship . The ships were mainly used during the Imjin War from 1592 to 1598.


The earliest references to turtle ships can be found in the annals of the Joseon Dynasty of 1413 and 1415. These ships were mentioned as ramming ships, which were mainly used against ships of the Jurchen and Japanese pirates . The armor on the upper deck of these ships consisted of up to 25 cm thick wooden panels, giving this type of ship its name.

Around 1591 the redevelopment of the turtle ships began under the Korean admiral Yi Sun-sin . The admiral, who was in command of the Korean Navy in Yosu at the time, anticipated the attack by the Japanese and was looking for a way to compensate for the numerical superiority of the Japanese. Contrary to popular belief, especially in the West, Yi Sun-sin did not design the ships himself, but only initiated the construction of the ships, while one of his officers, Na Dae-yong , did the actual construction. The first of the new turtle ships was launched on April 12th (March 27th according to the Chinese lunar calendar) 1592, just a day before the Japanese invasion of Korea began.

In the naval battles against the Japanese, Admiral Yi Sun-sin used combined fleets from Panokseon , the standard warship of the Korean Navy, and turtle ships. With this combination he achieved some spectacular victories over numerically superior Japanese fleets.

After the war, larger turtle ships were built whose dragon head was replaced by a turtle head. In 1782 around 40 turtle ships were in use.


The construction of the turtle ships was strongly based on that of the Panokseon . Both were - due to the shallow coastal waters of Korea - flat, barge-like ships, each with a lower, intermediate and upper deck.

The turtle ships came in different designs. The ships varied in size and equipment. What they all had in common was that they had a trunk made of spruce wood and the sides were armored with wooden panels up to 12 cm thick. The length of the ships varied from 30 to 37 meters. The hull had three decks , cabins and storage rooms were on the lower deck, the rowers sat on the intermediate deck and the cannons and soldiers were on the upper deck. The upper deck was provided with iron spearheads to ward off boarding attacks.

Was driven by the turtle ship sails , one or two masts with in each case a rectangular sail, and eight belts on both sides which have been served by a total of eighty rowers. The ship was held together by wooden nails, which on the one hand had the advantage that these nails did not rust, on the other hand they absorbed part of the water, expanded and thus ensured a more stable connection of the planks. Additional, interlocking beams supported the upper deck and reinforced the structure of the hull. At the bow a wooden dragon head stuck out, and below this head there was a spur, shaped like a face, just below the waterline.

The construction of turtle ships was an expensive undertaking, as tons were needed in building materials and numerous workers. The most important raw materials and objects were wood , iron , weapons (especially cannons ) and navigational instruments ( compass ). Workers, shipbuilders, ballistics engineers , designers and others had to work a considerable amount of time to complete a turtle ship. However, these circumstances were accepted because of the fighting power of the ship.


The crew of the turtle ships consisted of up to 80 rowers, each with five men forming a unit who operated one oar . Around 50 soldiers were on board, including the captain and the other seamanship. The fighting force consisted of artillerymen and archers. In some cases, landing troops were also transported on the larger turtle ships.


Turtle ships were equipped with 24 to 36 cannons , mostly 30, with eleven on each side and two on the bow and stern. Other guns were in the bow below the dragon's head.

There were cannons of different designs in use. They were named Cheon (heaven), Ji (earth), Hyeon (black), Hwang (brown) and Seung (victory). The Seung was the lightest cannon and had an effective range of 200 meters, while the Cheon was the most powerful with a range of 600 meters. The Hyeon and Hwang were medium-sized and mostly fired with incendiary bullets . The Hwacha was a kind of multiple rocket launcher that was also available at the time of the turtle ships; however, the direct use of this weapon on the ships has not yet been proven.

The dragon head itself also served as a weapon. Its fearsome appearance was intended to intimidate the opponent, and on the other hand, by burning a mixture of sulfur and nitrates inside the head, a poisonous smoke could be produced, which restricted the view and additionally contributed to the confusion of the opponent. In addition, the dragon's head was constructed in such a way that a cannon could also be fired through its mouth. The spur below this sculpture was used as a ram to attack enemy ships. There were also up to 100 small openings in the hull that archers used as loopholes.


Despite their size and weight, the turtle ships were relatively fast and agile thanks to their rowing crews, so that they could practically “run over” smaller ships and ram larger ones during a battle. Equipping them with cannons of different ranges and calibres enabled them to attack enemy ships at long, medium and short distances, including close combat.

In order to be able to counteract the tactic of boarding a ship that was common in the Japanese Navy at that time , the upper deck of the flat-built ships was covered with long iron spikes.

All openings in the fuselage were designed so that the crew could see out, but the enemy could not see inside. As a result, the crews of opposing ships were barely able to observe the preparations for firing the cannons, for example to take advantage of a break in fire to board the ship.

Upper deck

Turtle ship
Turtle ship from 1415, the picture does not show any iron armor

There is insufficient evidence for the claim, sometimes made in the literature, that the upper deck of the turtle ships is armored with iron plates. In general, the contemporary sources are so silent about the construction of the turtle ships that “we even know only limited information about the general conception of their construction”. There are two main sources of useful information, the Korean and Japanese war reports.

Contemporary Korean War Reports

Korean primary sources do not mention armor on the ships:

Admiral Yi Sun-sin himself does not mention an iron-armored roof in his extensive war diary. However, in a war report from June 14, 1592 he once wrote of "iron spikes" protruding from the roof:

“... in view of the threat of the imminent Japanese invasion, I built a turtle ship especially for this purpose, which has a dragon head on the bow, through whose mouth you can shoot cannons and whose back (upper deck) is provided with iron spikes (against enemy boarding). The crew inside can watch the enemy outside without being seen from outside. The ship can penetrate among a few hundred enemies and take them under fire ... "

The nephew of Admiral Yi Pun, who witnessed the war, briefly mentions in his biography that the upper part (the upper deck) was covered with planks that were studded with blade-like tips, but without further details regarding the material used and without mentioning iron plates.

16th century turtle ship in a picture from 1795

Contemporary Japanese War Reports

A Japanese war report called Ship Battles in Korea contains a description of a battle on July 9, 1592 by two Japanese commanders:

“At eight in the morning the enemy fleet (Yi Sun-sin's fleet), which consisted of 58 large and about 50 small ships, attacked ours. Three of the big ships were blind ships (turtle ships) covered with iron. "

However, the text, which refers to events three weeks after Yi Sun-sin's description of the turtle ships, gives no further indication of whether the upper deck or the iron spikes protruding from the upper deck, as briefly described by Yi Sun-sin, were meant previously described.

Later sources

No contemporary images are known, so the first picture of a turtle ship does not appear until Admiral Yi 's Complete Writings , published for the first time two hundred years after the war in 1795. The brush drawings in the book differ in important details from the war reports: While the hexagonal structure of the upper deck can lead to the belief that the turtle ships had iron ceiling panels, the unexplained lack of attested iron spikes has to complain about the "lack of realism of the Brushwork by the Draftsman ”, which raised“ questions about the authenticity of the war reports ”.

It should be mentioned that the iron armor of the turtle ships, if it existed, was due to very different considerations than the ironclad of the 19th century: While the hull of the ironclad was covered with iron to protect the ship from enemy artillery fire, the iron roof of the turtle ship should serve to prevent the Japanese from boarding.

Application area

Turtle ships were mainly developed for defense, to ward off troop landings or to disrupt or at best prevent enemy supplies. The further use consisted in escorting other ships. In sea battles, mostly during the Imjin War, turtle ships were used to attack.

The use of the turtle ships

Imjin War: Siege of Busan by Japan

With the landing of Japanese troops under General Toyotomi Hideyoshi not far from Busan , on the south coast of Korea, the Imjin War between Japan and Korea began on May 23, 1592 . Within three weeks, Japanese troops overran all Korean defenses and captured the capital, Seoul .

Around this time, Admiral Yi Sun-sin's fleet intervened in the war. Turtle ships were designed for defense, but the tactics used by Admiral Yi Sun-sin made them suitable for attack.

The first sea battle of Yi Sun-sins against a Japanese supply fleet took place in 1592 not far from the port of Okpo . During the battle, the approximately 24 Panokseon of the Admiral destroyed 13 of the approximately 50 Japanese ships, while only one ship was slightly damaged on the Korean side. Turtle ships were not used in this battle.

The first use of the turtle ships took place during the Battle of Sachon on May 29, 1592. Yi Sun-sin's original plan was to attack a Japanese fleet that was anchored in the port of Dingson. However, since the high cliffs above the city would have allowed the Japanese soldiers to attack the ships from above, Yi Sun-sin changed his plan and had his squadron turn around under the eyes of the Japanese and head for the open sea.

The Japanese fleet commander saw the supposed escape of the Koreans and let part of his fleet take up the chase. Thereupon Yi Sun-sin turned his squadron again. The Koreans' attacking leaders immediately fired at the Japanese. Yi Sun-sin's flagship, a heavy turtle ship, broke into the line of the Japanese and fired from all cylinders at close range. The Japanese had nothing to counter the concentrated fire of the Koreans, so that it was possible to sink all Japanese ships, while on the Korean side only four seamen, including Admiral I, were slightly injured.

Admiral Yi Sun-sin used this tactic again and again with modifications and defeated superior Japanese fleets in nine naval battles. The heavier turtle ships ran after the fast Panokseon, after a turning maneuver they formed the front of the attack against the Japanese fleet and could ram enemy ships at close range and sink them with their concentrated cannon fire or set them on fire.

In the naval battle of Chilcheonryang on August 26th and 27th, 1597, however, the entire population of turtle ships was destroyed along with almost the entire rest of the Korean fleet because their commander at the time, Won Gyun (Yi Sun-sin had been deposed by a plot) prematurely had taken action against a Japanese superior force. After the victory over the Japanese, the turtle ship was apparently no longer used widely; in the historical records after that time there are no reliable indications of its further use.

Turtle ships today

The greatest legacy of the turtle ships can be found in South Korea , where several replicas have been made, including by a South Korean electronics company that sees this as "their expression" of " winning the economic war against the Japanese," the company's management stated.

See also


Web links

Commons : Turtle Ship  - Collection of images, videos and audio files

Individual evidence

  1. ↑ As is usual in Wikipedia articles, the most common word in the modern language is given instead of the character 龜 船 pronounced in today's Korean gwiseon , the then dominant Chinese script.
  2. Yisunsin.prkorea.com: Admiral Yi Sun-shin People
  3. Jung-ja Holm: Admiral Yi Soon-shin. A brief overview of his life and work. Diamond Sutra recitation group. ISBN 0-9779613-0-3 . P. 32.
  4. ^ Samuel Hawley: The Imjin War. Japan's Sixteenth-Century Invasion of Korea and Attempt to Conquer China. The Royal Asiatic Society, Korea Branch, Seoul 2005, ISBN 89-954424-2-5 , pp. 195f.
  5. a b c d Stephen Turnbull: Samurai Invasion. Japan's Korean War 1592-98. Cassell & Co, London 2002, ISBN 0-304-35948-3 , p. 244
  6. ^ Roh, Young-koo: Yi Sun-shin, an Admiral Who Became a Myth. In: The Review of Korean Studies. Volume 7, No. 3 (2004), p. 13
  7. ^ Hae-Ill Bak: A Short Note on the Iron-clad Turtle Boats of Admiral Yi Sun-sin. In: Korea Journal. Volume 17 No. 1 (January 1977), p. 34
  8. ^ Hae-Ill Bak: A Short Note on the Iron-clad Turtle Boats of Admiral Yi Sun-sin. In: Korea Journal. Volume 17 No. 1 (January 1977), p. 35
  9. ^ Hae-Ill Bak: A Short Note on the Iron-clad Turtle Boats of Admiral Yi Sun-sin. In: Korea Journal. Volume 17 No. 1 (January 1977), p. 36
  10. ^ A b Hae-Ill Bak: A Short Note on the Iron-clad Turtle Boats of Admiral Yi Sun-sin. In: Korea Journal. Volume 17 No. 1 (January 1977)
  11. Zae-Geun Kim: An Outline of Korean Shipbuilding History. In: Korea Journal 29:10 (October 1989), p. 10.
  12. Kenneth M. Swope: Crouching Tigers, Secret Weapons: Military Technology Employed During the Sino-Japanese-Korean War, 1592-1598. In: The Journal of Military History. Volume 69 (January 2005), p. 32