A man from eastern China's Anhui province recently built a small submarine that is capable of sailing 7 nautical miles per hour, chinanews.com reported. The hand-built submarine also won its creator a patent certificate.

The man, named Zhang Shengwu, is a 51-year-old businessman who enjoys working on new inventions. One day, after watching a TV program about submarines, he decided to make one himself, despite opposition from his wife.

It took Zhang about two months to complete the submarine, which is 6 meters in length, and about 60 centimeters in width inside the cabin. The height is a little under 1.5 meters.

Zhang admitted that he was unable to install proper oxygen-supply equipment due to insufficient space in the cabin. Instead, he selected an alternative air duct to supply oxygen, which unfortunately limits the depth the submarine can reach to 1 meter underwater.

Now that Zhang has patented his submarine, he is planning to explore rescue boats.