Han asked Gu to shelter inside the boat, while he remained at the boat's bridge. If the engine had got damaged, in likelihood they would have been claimed by the inky depths.

"It feels like a man running in the wilderness, with constant thunder and lightning so close that you can touch death," Han said in his blog.

After 12 hours, the pair finally broke free of the storm and calmer seas prevailed. Han concluded that "Nature can do whatever it wants to screw you" and that "family matters most".

Running out of fuel and only half way to their next port of call, the two floated for three days without phone signal and hope of rescue before finally arriving at an industrial port in Denmark.

The next day, Gu told Han that he wanted to quit and fly back home. The experience also made Han really understand the meaning of his parents' words-"come back alive".

After Gu left him in Amsterdam, Han chose to continue the voyage on his own, because "he has devoted everything to the boat and there is no turning back".

In September, Han, alone, sailed nine days nonstop to pass through the Mediterranean Sea. He set his alarm clock to ring every 20 minutes, to wake him up and check the route and incoming weather.

In one of his blogs, Han said that if loneliness can be scaled, solo sailing must be included.

To mark his solo voyage across the Mediterranean, Han wrote on social media that "Entering the storm at sea. Thank you god for not killing me. Salute to life."