A man from Shenmu county, northwest China's Shaanxi province, is building his own submarine, which has so far cost him more than 300,000 yuan ($48,344) and will take at least another 300,000 yuan to complete, the Chinese Business Daily reported on Monday.

The 9.2-meter-long and 3.1-meter-high submarine weighs over 18 tons and can house about 15 people. In theory, it can dive as deep as 60 meters, according to Du Xiutang, the submarine's creator.

The high school dropout began designing and building the submarine in August 2014 and has completed the main body of the machine, including engines, dynamos, an oxygenerator and a periscope.

Du plans to test his invention this summer.

If an emergency occurs, the submarine can surface quickly by draining away water using hydraulic pressure, an improvement from traditional designs, he added.

Du got the idea to develop a submarine after learning in 1992 that China had paid a high price for a discarded Russian submarine.

He has got three national invention patents since 2015 in submarine hydraulic drainage system, fluid-link steering technique, and double helix propelling system.