Submarines have been conceived for many years, but only became practical in about 1900. Submarines have changed a lot in design from their first making which was in the years B.C. This sub was a box held under water with big ropes. New submarines are nuclear powered and can move at a speed of 30 knots and are big war weapons.
The first submarine that could stay under water on it's own and move on it's own was built in about 1620 by Cornelius van Drebbel. It was a rowboat surrounded by leather.
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