Editor's note: China Marine Surveillance has increased its patrols in Chinese territorial waters in recent years. A China Daily reporter joined the third patrol to the South China Sea this year, from March 5 to 20, to get a taste of life on board.
The ship is swaying from side to side so violently that everyone in the pilot's cabin has to catch hold of handrails or sit tightly on chairs that are fixed to the floor, to avoid falling.
Seen from the window, the boundless sea seems to slope when the ship descends to the trough of a wave, tossing the ship up and down and making people feel nauseated, as if they were in a malfunctioning elevator that is rising and falling constantly.
To the occasional passenger, the jostling may seem like something out of a nightmare. But to the young pilot of the ship, who is still in his 20s, these are simply the conditions in which he works. And they have been worse.
"This is not a real storm," said Wang Yanhui, 29, who has served as one of the helmsmen of Haijian 83 of the China Maritime Surveillance Force for four years.
"I have seen storms that tossed the ship six meters up and tilted it 30 degrees, when everything in the room that is not fixed down slips and falls and everybody reaches for the buckets to throw up in."
Like other surveillance vessels operated by the South China Sea branch of the country's oceanic administration, the ship sails the seas periodically to investigate reports of illegal fishing or oil exploration in Chinese waters, as well as other violations.
For Wang, piloting a ship in the force charged with enforcing China's maritime laws came as the fulfillment of a childhood dream.
A native of Central China's Henan province, Wang grew up eager to know what the sea looked like. Interested in the military and hoping to join the army, he applied to attend a navy college after graduating from senior high school.
"Unfortunately, I failed an eyesight test and wasn't accepted by that college," he recalled, pointing to his glasses. "So I chose to major in sea navigation at another college."
At school, he saw the sea for the first time, a sight that proved to be a disappointment.
"I always pictured the sea as being crystal blue," he recalled. "I did not expect the coastal sea to be yellowish."
Before graduation, Wang passed a test given by the State Oceanic Administration and was assigned to a ship. He had to take an internship for a year, pass strict exams and get a license. Only then could he get behind the helm of the 3,000-ton surveillance vessel.
Yet even when dreams do come true, they often are not as sweet as a person had imagined. Wang found life at sea not to be as romantic as he had envisioned. The initial excitement of sailing on vast blue waters and enjoying the sight of a rosy sea surface at sunset quickly faded and was replaced by formidable difficulties.
"Life is quite boring at sea," Wang said.
"For months in the deep ocean, all you can see is boundless water, except for the oil rigs or fishing boats that occasionally appear."
Seasickness, as it is for many other seamen, was the first obstacle Wang had to suffer when he began his life at sea. He recalled that a storm had come upon his ship during his first trip into the South China Sea. Being tossed about on board made him so sick that he couldn't eat anything without throwing up and was reduced to lying in bed for three days.
"I had a piece of watermelon on the fourth day but threw it up immediately," he recalled.
Later Wang, like other crewmen aboard the ship, gradually got used to life at sea and came to tolerate the seasickness.
"Even the most seasoned seamen would vomit when the storm gets nasty," Wang said. "But it's no big deal at all. For us, vomiting is something as common as having meals."
Luckily for him, the ship he now pilots is equipped with the latest equipment. That, added to the knowledge and experience he gained at college, means that steering the ship does not place particularly heavy demands on him.
The ship is guided by a precision electronics system, and Wang only has to steer by hand when the ship comes too close to another or when it is entering a harbor.
Technology has made life far less arduous for Wang and his dozens of shipmates. They can eat fruit every day, live in air-conditioned rooms and even watch satellite TV programs.
Wang works two shifts every day - from 8 am to noon and from 8 pm to midnight. When he has nothing to do, he can play table tennis and computer games.
Despite the onboard entertainment, Wang can still feel low in spirits when at sea. His job calls on him to embark at least 10 times every year, causing him to be away from his family about 200 days in a year.
"Mobile and Wi-Fi signals vanish as soon as the ship sails into public waters," he said. "I miss my wife and 2-year-old baby all the time and the only thing I can do is to look at their pictures."
Wang said that every time one of his short reunions with his family comes to an end and he must prepare for another voyage, he always finds it hard to say goodbye.
"I sometimes even wish there was something wrong with the schedule so I could stay at home for one more day," he said.
Speaking of his job, Wang said he has mixed feelings toward it.
"This work is hard, to tell you the truth," he said. "But it's important to safeguard the oceanic interests of our nation, and someone has to do this work."
Although China's maritime surveillance force, like Wang, has accomplished much and made many sacrifices, it still remains mysterious and largely unknown to the public. Wang said that bothers him very little.
"I don't care whether our work is recognized or not," he said. "I am proud of dong this job. We have accomplished many concrete things for our country. As long as I am needed, I will continue to serve."
Reporter's Log: Finding my sea legs while inspecting troubled waters
I was ecstatic as the ship approached the bank of the Pearl River. The mere sight of land and the expectation of standing on it again were so thrilling.
This is how I felt after spending 16 days on board a ship where everything was on the move and undulating.
But when I stood on dry land again, the moving sensation didn't stop. I had to learn how to walk again after completing a 3,300-nautical-mile (6,100-km) journey on the South China Sea.
The journey started on March 5, when two vessels of the China Marine Surveillance set out from the southern port city of Guangzhou on the third patrol this year, targeting the illegal exploration of oil and gas. I was on the 3,000-ton Haijian 83, the larger of the two ships.
As the ship sailed south, murky costal waters became green, and within half a day all I could see while standing on deck was boundless blue water. In the following days, the ships passed the waters of China's Xisha and Nansha Islands, and went as far as the shoal of Zengmu Ansha, the southernmost point of China's territory.
Haijian 83 has a crew of about 40, working mainly as deckhands or in the engine room.
The ship is equipped with the latest technology, which lessens the burden of duties on board, but the working environment is still harsh.
Those working on the ship's bridge, the control center, suffer more from the effects of the sea's swell and waves, being highest placed on the vessel, while those in the engine room, below the surface, have more stability but work in constant noise and heat.
Every morning the CMS' law enforcement officers come to the bridge to check the radar display screen to see if any illegal oil rigs had appeared in Chinese territorial waters.
Most oil rigs have several floors, and some burn off gas, shooting flames so high into the sky that they can be seen miles away, even in intense tropical sunlight.
Investigating these rigs is the busiest moment for all on the bridge. One officer sits in front of the radar screen, noting the distance and direction of the rigs. Another observes a different screen and records the ownership of the rigs, and is in radio contact with them. A CMS interpreter stands by to translate. The captain supervises operations, waiting to discover whether the rigs are authorized to drill.
The captain believes the number of oil rigs operating illegally in Chinese territorial waters is "enormous".
The South China Sea branch of State Oceanic Administration issued a notice saying more than 30 foreign oil rigs were spotted along the route of our patrol alone.
Usually, CMS officers only take photographs and make a record, and the ships sail past the rigs without disrupting their operation.
As we sailed south, more and more rigs appeared. At one time, I counted eight in the sea around us, some only a mile apart from others.
When we sailed close to one after dusk, the giant platform, beaming golden light, dwarfed our vessel and lit up the sea around us.
And that was as exciting as it got. At least we were spared the dramatic events of rough seas and the utter despair of seasickness, which defeats even the most seasoned of seamen.
I was lucky. The sea remained calm most of the time. The captain told me it was the best time of the year for a sea voyage, as we had missed the cold fronts from north, and the typhoon season was not yet upon us.
However, just as I was counting my blessings near the end of the voyage, the sea swelled in power and rocked our boat. I spent a terrible night vomiting and getting no sleep.
As I was returning to Beijing, happy and relieved, I also felt a sense of loss after saying goodbye to those with whom I had spent 16 days.
They are a special group, living a different life from most of us, and almost invisible to the society. Some have been at sea for 40 years safeguarding the nation's oceanic territory, often spending 200 days on voyages and separated from their families for most of the year.
The commander on my ship gave up a merchant navy salary six times higher to join the CMS 20 years ago.
Some of the crew were still training and hoping to get navigation certificates.
Then there was the translator, in her 20s and the only woman on board, whose favorite pastime on board was singing. And the captain, a history buff. He told me he read all the history books in the college library when he was a student.
Just as we were disembarking at Guangzhou, I heard an announcement on board that all crew should return to duty two days later.
I hoped they could stay with their families for a few more days before they sailed out on another mission.