Korean Turtle Ships
a.k.a. Geobukseon or Kobukson
Class of Ship
The vessel pictured above is a 1:2.5 scale
reproduction of a turtle ship housed in the War Memorial Museum, Seoul Korea.
This is regarded the most historically accurate reproduction of such a vessel.
Originally developed in 1413 the kobukson, or 'turtle ship', began as an updated
version of the kwason, or 'spear ship' (designed for ramming enemy vessels in
combat). The turtle ship is probably the most famous class of vessel to exist in
Korean naval history. However, the initial design of this craft only generally
resembles that of those built later in the 16th century which culminated in the
famous battleships of 1592.
As is common for most famous weapons systems the
turtle ship did not suddenly emerge, but rather evolved from earlier and less
refined designs. The immediate ancestor of the turtle ship was the p'anokson
which functioned as the workhorse of the Korean navy both before and throughout
the time of the turtle ship (normally outnumbering the turtle ships in combat).
It's most noteworthy features are that it has two decks, an upper deck where
troops would be stationed and an enclosed lower deck to protect the oarsmen in
combat; a 'castle' situated centrally on the upper deck, used as a command and
observation post by the captain; and high sides designed to repel boarders. This
last point is significant as the Japanese, Korea's long-term and primary naval
adversary, would typically attack an enemy ship by boarding it.
Following on from the p'anokson the original turtle ships featured high sides
and two separate decks. However, they typically omitted the inclusion of a
'castle' and were originally designed with the emphasis of being able to be used
to ram and damage an opponent's ship without suffering damage themselves.
Because of this they were boxy and very solidly constructed, as has been
historically typical of Korean warships, but even more so in this case.
design was taken to its ultimate conclusion in the 16th century by the legendary
Korean naval figure, Admiral Yi. These improvements included a completely
enclosed and overhung upper deck. This was shared by the gunners and oarsmen and
was covered over by a sturdy, curved, roof. Armoured plates to which spikes had
been attached would form an outer skin making this roof both tough and
practically impossible to walk across. As a final touch these spikes would often
be obscured by straw or mats to lure in unsuspecting boarders.
On the sides of the upper deck gun ports were positioned, allowing the firing of
cannon or for use by archers. There were also additional ports at the bow and
stern of the ship.
While the open decked p'anokson made an ideal platform for carrying out
remote bombardment the advanced turtle ships of the 16th century were best
suited to rapidly moving in to engage enemy vessels up close and break up enemy
lines before quickly withdrawing. While turtle ships of this vintage were still
occasionally used to ram enemy ships they were now generally seen as too
valuable to risk in a collision with another ship. Also despite their power and
their fame it was uncommon for more than five of these vessels to see action in
any one battle.
the transmission of gunpowder technology from Ming dynasty China in 1373 the
Koreans rapidly developed a highly advanced range of naval artillery. By 1410 it
was common for their ships to be armed with a variety of cannon with records
showing that at this time they possessed 160 ships of war with artillery on
board. This marked a turning point where the Koreans began to favour an approach
similar to that of the Chinese. This emphasised the bombardment of enemy vessels
rather than attacking by ramming or boarding them.
These weapons included deck mounted mortars which fired the Korean version of
Chinese 'thunder-crash' bombs - a hard-cased fragmentation projectile. They also
used four classes of commonly used cannon, as distinguished by their size, which
were typically mounted on mobile wooden carriages (as shown below).
these cannon would fire stone or iron balls, the preferred projectile weapon
used by the Koreans at this time was a giant arrow with an iron tip and iron or
leather fins (shown right). While these may look like rockets they were not
self-propelled but rather fired from a cannon. The largest of these measured up
to nine feet (around three metres) long. These projectiles possessed both a
longer range and greater accuracy than ball shot but had equivalent destructive
They also had the advantages that upon impact they would both damage the
ship and also often shatter, spraying deadly splinters of wood among the crew of
the ship they hit. As well as this, they could be easily converted into fire
arrows. Turtle ships would typically be armed with a full range of normal
cannon, firing both ball and arrow projectiles, as well as being crewed by a
number of archers.
Fighting Ships of the Far East (2) by S. Turnbull. Osprey Press, 2003.
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