"The regular training sessions and not being able to leave the camp can make life a little boring. We need to improve our mood on our own and avoid becoming emotional. Usually, we play basketball, snooker, phone games or just chat and joke with each other," he added.

In addition to those activities, Chen said the sailors have a special place to lift their spirits when they feel down.

"About 20 minutes' walk from the camp, there is a large stone facing the sea that few tourists visit. When we have time, we like to go there alone, to stare at the sea or even shout at it.

"Usually, we shout: 'XXXX, I miss you!' or 'Yes, you can do it!' and 'Don't be afraid!' Sometimes if someone happens to be passing and hears our words, they shout back 'Forget about her' or 'You mustn't miss her'," Chen said.

The stone also offers a useful retreat when squad leaders need to help members of their team deal with loneliness or depression. They often take unhappy team members to the stone and chat with them privately.