Jack's model of a Korean Turtle Ship.
This was a type of large Korean warship that was used intermittently by the Royal Korean Navy from the early 15th century up to the 19th century. The ship's name comes from its protective shell-like covering.
Turtle ships were equipped with different types of cannons. Their most distinguishable features was a dragoon-shaped head at the bow that could launch flames or smoke from the mouth. Each were also equipped with a fully covered deck to deflect arrow fire, musket shots and incendiary wapons.
The deck was covered with iron spikes to discourage enenmy men from attempting to board the ship.
Jack made a mold and cast all the 'metal spikes' individually.