In order to be realistic, the director asked two landscaping experts to be responsible for building the small German submarine and the American Type S submarine for World War II respectively. However, because there are few photos of the S-type submarine, the military unit refused to leak the internal structure diagram for safety reasons, which made the plan to rebuild the American submarine face a crisis. Fortunately, it was helped by a senior naval officer Hanifin. S submarine reappears on the screen. Both submarines have internal molds made according to the standard size of 1:1, and the internal structure is the same as that of the year. Among them, the U571 weighs 600 tons, which is reproduced and restored on a universal steering system. This system allows the submarine to move up and down at any angle, sink, and sail in the sea. It amazed an officer who fought on such a submarine, as if he was back in World War II.
In order to make the effect of the submarine more realistic, five 50-foot-long submarine models have been completed, each with different functions, some can move forward, some can dive, and some can launch torpedoes. It is enough to represent the assault and underwater movement of a real submarine in the deep sea.
