A karaoke competition is held after training. [Photo by WANG ZHUANGFEI/CHINA DAILY] 

In addition to the weather, the repetitive nature of life and isolation make living on the island tough.

At all times of the day, the sailors monitor radar screens to watch for dangers on the sea and provide the teams in the hilltop base with information. Each sailor takes alternating six-hour stints at a screen during their 24-hour shift.

It takes about six hours to sail from Dongfushan to Zhoushan, the nearest city, but between June and November, when typhoons make landfall on the island about five or eight times, no vessel will approach the rocky outcrop. 

There is a saying among the veteran sailors that after a prolonged stay even pigs stare blankly the whole day and dogs try to escape by jumping into the sea.

Chen Zonglei, a 24-year-old in charge of the camp's armory, said he will never forget when he was a new recruit and had no annual leave. Some friends planned to visit him, but a typhoon prevented them.

"At the time, I had not visited my hometown for a while. I really hoped they would come so I could show them around the island. I felt it was a real pity they couldn't make it," he said.