Wang Lianmiao (1st L) checks sailing conditions using telescope aboard the Maple Star on the Yangtze River in east China's Jiangsu Province, April 24, 2013. Wang Lianmiao and Zhu Hui arrived at the port of Jingjiang on the morning of April 24, 2013. Both men are inland waterway pilots from the Yangtze River Pilot Centre. Awaiting them was the Maple Star, a 180-meter-long Marshall Islands-flagged cargo ship with a gross register tonnage of over 23,000. Under their pilotage, the Maple Star was to veer 180 degrees and head downstream to the port of Zhangjiagang. The role of pilots becomes increasingly significant as foreign vessels that navigate on the Yangtze River grow in number and size. Given the intricate waterway distribution along the Yangtze, Chinese pilotage is mandatory for foreign ships entering the river's mouth to avoid accidents and protect the country's sovereignty. Zhu Hui graduated from the Navigation Institute of Jimei University and started to work as a pilot in 2005. He is still not authorized to guide vessels like the Maple Star on his own. Wang Lianmiao, who has been in the field for 20 years, was assigned to cooperate with him. The two of them know well the winds, tides, currents, shoals and reefs of the water area. With the aid of modern technology and floating signs, they are capable of issuing appropriate commands regarding the vessel's direction, route and speed. Docking and undocking large vessels like the Maple Star require particular prudence. Any mis-manoeuvre could delay the port's schedule or even damage port facilities and the vessel itself, causing economic losses. At such times, a pilot's commands are crucial to ensure navigation safety. When the Maple Star approaches its destination, Zhangjiagang, Wang Lianmiao went onto the deck to check the vessel's surroundings. "SLOW AHEAD!""PORT 30!""STOP ENGINE!" Wang would give such orders to the captain. The latter in turn repeats them to the mariners, who would follow the orders. "It's not easy doing a pilot's tasks," said Zhu. "Since there are only around 360 of us along the Yangtze, we are busy most of the time. Nearly one third of our work is done at night." Sometimes a pilot has to risk his life while working. A staff at the Yangtze River Pilot Centre told us that it is quite common for a pilot to board a foreign vessel via swinging rope ladders, which are especially tricky to climb on windy days. There were pilots who got hurt or even died after falling from rope ladders. Zhu Hui said it was solely by chance that he became a pilot. "The choice was at first a little uncommon -- most of my classmates became sailors. But it now seems the path for me." (Xinhua/Li Mangmang)

Wang Lianmiao (1st R) contacts nearby ships via high frequency radio aboard the Maple Star on the Yangtze River in east China's Jiangsu Province, April 24, 2013. (Xinhua/Li Mangmang)

Zhu Hui goes between the cockpit and the deck to check the Maple Star's sailing condition on the Yangtze River in east China's Jiangsu Province, April 24, 2013. (Xinhua/Li Mangmang)

Zhu Hui has lunch during the Maple Star's voyage on the Yangtze River in east China's Jiangsu Province, April 24, 2013.  (Xinhua/Li Mangmang)

Wang Lianmiao (L) and Zhu Hui leave the Maple Star after the vessel is safely docked at the port of Zhangjiagang in east China's Jiangsu Province, April 24, 2013. (Xinhua/Li Mangmang)

Zhu Hui checks sailing conditions using telescope aboard the Maple Star on the Yangtze River in east China's Jiangsu Province, April 24, 2013. (Xinhua/Li Mangmang)

Zhu Hui checks sailing conditions using telescope aboard the Maple Star on the Yangtze River in east China's Jiangsu Province, April 24, 2013. (Xinhua/Li Mangmang)

Wang Lianmiao gives docking commands as the Maple Star approaches the port of Zhangjiagang in east China's Jiangsu Province, April 24, 2013.(Xinhua/Li Mangmang)