Hua Ming gives directions to take the submarine deep into the sea.

During an international joint drill in 2012, Hua and his submarine received a mission to dodge four foreign anti-submarine ships and one helicopter in a narrow area.

"Put it in simple terms, the possibility of our submarine being discovered is 99 percent. Regular tactics can hardly win the battle," says Hua.

Hua decided to hide the submarine in an area with the most complicated underwater environment - where it was also the most difficult to operate the submarine.

Hua waited deep under the sea until a merchant ship passed out of the drill area. Using the noise made by the merchant ship as a cover, the submarine successfully escaped the foreign search web.

"The passing of a merchant ship might be a coincidence, but hiding under the sea with high temperatures and high pressure for dozens of hours showed our perseverance," he says.

When submarines are hiding under the sea to wait for breakthrough opportunities, air-conditioners are shut off to both save energy and avoid making sound. Temperatures inside the submarine can be as high as 38 C, with nearly 100-percent humidity.

In his peers' eyes, Hua is just crazy about submarines.

Li Panjin, officer in charge of sonar operation, still remembers the first day Hua came to the fleet in 1999 after he graduated from the People's Liberation Army Navy School of Submarine.