The Pacific Ocean was far from passive.

This has been the case for all international races and competitions in the oceans. Meanwhile, in its natural state, the ocean is truly characterized by dramatic turbulences and billowing waves. There are waves a few metres high that reach the sky, even without wind. They are like giant and relentless beasts waiting for the opportunity to pounce.

At 20:00 on July 15 2011, the Xiangyanghong 09 reached the designated test area at 10°07' N and 154° 13' W after a voyage of 15 days and four hours. It met with Haiyang 06, the scientific expedition ship of the Guangzhou Marine Geology Survey that had arrived on the evening of the July 14, 175 degrees and 550 nautical miles from the main island of Hawaii. Haiyang 06 was engaged in July 23 scientific expedition and it supported the Xiangyanghong 09 in the Jiaolong's sea trial in terms of security and parameter guarantees in the trial environment.

The northeast Pacific Ocean was looming with even worse weather conditions. Su Bo, the forecaster responsible for weather support from the NMEFC, was knitting his eyebrows together with concern. Ever since the test area for the start of the preparations had been chosen for the 5,000-metre sea trial, Su Bo had done his homework and researched several sea trials. He believed that every July this area would usually witness winds of seven meters per second and waves of 1.5 metres, which are quite reassuring. Sailors familiar with the area also told him that the sea was calm in this season, so calm that it even resembled a mirror. He reported such conclusions to the leading group, providing people with hope for good sea conditions during the trial.

However, things did not happen as expected. Not until they arrived at the area did they find that they were totally unprepared for the weather conditions. Local severe convective weather processes and a tropical cyclone, which had drawn forecasters' attention, did not take place as expected. Instead, fierce winds from the northeast and lots of spray persisted, which was in sharp contrast to the calmness depicted by previous visitors to the area. Experienced sailors know very well that white spray on the sea is an indicator of a wind of force six to eight and of waves of four to five metres high, which is anything but good conditions for sea trials. What caused such abnormalities?

This sea area is at the south edge of the sub-tropical high in the eastern Pacific Ocean, which, in meteorological terms, is subject to the northeast wind or the northeast trade wind. In most cases, the sub-tropical high strengthens and moves northward in summer and weakens and moves southward in winter. Therefore, the northeast wind in summer is far milder than in winter. However, this July saw an above-average intensity index of the east Pacific sub-tropical high and a more southerly position compared to previous years. As a result, the winds were heavier and the conditions in the waters were more adverse.

Lightning and thunder lasted for days, compounded by pouring rain and east and northeast winds of force six to seven, as well as waves of two to three metres. The vessel was shaken violently, causing seasickness for many of the team members. It was already difficult to walk and to keep the on-board equipment in good shape, let alone diving the Jiaolong for the scheduled sea trial. One day, the installation and insurance group was doing check-ups on the rear deck when the slap of a big wave left the vessel tilting from side to side. An oil bucket weighing tens of kilograms drifted like a rock rolling down a slope, only to hit the winch. The technician of the 702 Institute, Zhang Jianping, rushed to intervene. The facility was kept safe but the ring finger on his left hand was injured and covered with blood.

"Zhang is injured. Call the doctor."

"I'm fine." In great pain, Zhang Jianping went to the clinic with his arm held by colleagues. The doctor on board sterilized the wound, stopped the blood and put three stitches into the cut. When he had finished, he tried to dissuade Zhang from staying at his post for fear of contamination. But Zhang insisted, "I know my job better than anyone. I can't give this work to others when the weather conditions are so bad!"

The changes on the "battleground" called for timely deliberations. On the evening of July 18, the on-scene headquarters held an emergency meeting to discuss what should be done next. Su Bo, the meteorologist, made careful judgements and forecasts of the weather and sea conditions on the basis of meteorological data regularly retrieved from the marine satellites. He observed that there were no signs of improvement in the sea trial area over the next five days. However, several latitudes away in the south there was the doldrums, or ITCZ, where the northeast trade winds of the northern hemisphere and the southeast winds of the south converge. The wind averages were below force five and this meant that the area could be considered as a back-up. The headquarters discussed the option and submitted it to the leading group in Beijing for approval. Finally, the mothership received the order to move southward to a particular point to conduct the sea trial.

On these orders, as if adopting guerrilla tactics, the Xiang 09 headed off to the south in an attempt to evade strong headwinds and billowing waves. At the same time, the headquarters ordered that all departments should be fully prepared during the voyage so that the dive could be conducted once the ship had reached the target area. The Jiaolong manned submersible, which used power-free diving and surfacing technology, required ballast to be installed prior to every dive. Not only skills but also strength was necessary for the preparations, which was even more demanding when sailing against the wind and the waves.

In one ballast installation, despite the rolls on the rear deck, the lift hoisted the 260 kg iron to the entrance of the submersible only to find that the bolts were of the wrong size. This was a rookie mistake that led to criticism from headquarters that evening. However, at that moment, it was urgent to suspend the installation and to immediately change the bolts. Suddenly, a big wave slapped the ship, tilting the lift that then dropped the iron onto the deck from a two-metre height. This sent a chill down everyone's spine. Luckily, no one was hurt. Having calmed themselves, the team members immediately returned to the frontier.

To make matters worse, rain began to fall, making the deck more slippery than before. What now? It was clear that the need to dive the next day did not allow for any delays; the installations had to be completed that day. The rain did not extinguish the passion of the sea trial members. The installation and insurance group joined the cause under the leadership of Cui Weicheng, the Vice Chief Commander. Even the oceanauts, members from the surface support system and members from the experiment department invited themselves onto the rear deck to accompany Chief Security Engineer Zhang Aiqun, Chief Commander Liu Feng, Secretary Liu Xincheng and Professor Yu, the leader of the expert group. More than 30 people gathered on the rear deck to pool their wisdom and contribute their effort.

Zhang Jianping, who orchestrated the work, was wielding a hand wrapped in bandages. Under his instructions, the team lifted the ballast iron of more than 200 kg to the forklift truck. Another senior technician, Gu Qiuliang, was using a steady hand to operate the forklift truck to the location of the Jiaolong's installation. The skidding ballast iron on the truck prompted joint efforts to push or carry the iron in order to keep it in position. Zhang Jianping and Deng Baoqiang ascended to the scaffold to marshal the lift and properly install the ballast iron. The storm became fiercer, as if all the water in the ocean was being sucked up and poured down from the sky. Drenched as they were, the team members needed only one attempt to place the ballast irons on both sides.

Then, while wiping water off his face, someone joked: "Look, Heaven was moved to tears!"

"Haha." Everyone laughed with pride.

A 24-hour overdrive finally led the team to the selected back- up area on the morning of 20th July. As expected, it was far calmer than the previous area. No time should be wasted before the dive. The main driver was still Ye Cong, in company with Cui Weicheng and Yang Bo. The mission included power-free diving and a surfacing test, a balance test, a key re-check of the ultra-short baseline positioning and a ground test, advance, power supply, position adjustment, hydraulic pressure, control, acoustic and life support tests and taking a water sample when the submersible was ready.

The team members were already in their respective places by 8:30 when CCTV began their live broadcast. Once prepared, the Jiaolong was filled with water ready to start diving at 9:10. Unlike the surface, the sea was calm and still hundreds and thousands of metres below. The first dive of the 5,000-metre sea trial thus began. It went well. At 11:09, the vehicle reached 3,759.9 metres, more than it had the year before. By 11:26 the Jiaolong had reached 4,027.31 metres. Suspended in water and following inspections, it started the tests.

Once a troublesome issue, the underwater acoustic communication system was very mature and effective thanks to the efforts of the CAS Institute of Acoustics, led by researchers like Zhu Weiqing and Zhu Min in the sea trial group. Four-thousand metres below the surface, the submersible managed to communicate with the mothership through digital signals and it transmitted multiple HD pictures of the deep sea and a touching group photo of the oceanauts. CCTV correspondent, Wang Kaibo, also telecommunicated with Ye Cong.

Due to the time difference, the live report was on air at 5:00 Beijing time. The leaders of MOST and SOA had to get up early to witness this great moment. The success of the first dive filled everyone's heart with great joy!

The dive did not break the 5,000-metre record but it proved to be outstanding preparation as it identified areas for improvement and identified the correct stowage based on the function tests. Having verified the effectiveness of the maintenance and upgrading that had followed the 3,000-metre trial, all the members of the sea trial gained greater confidence about their ability to achieve the 5,000-metre breakthrough. Since that time, it has become normal to evade high waves in search of ideal sea trial areas.

However, the winds and waves of the Pacific Ocean, which are parallel to relentless enemies, do not give up easily. The ocean made a silent and sinister comeback when both frontline and support teams were celebrating the good start.

According to the plan, the second dive was to be launched on 21st July when the new 5,000-metre record was to be challenged in order to keep up the good momentum. CCTV and other mainstream media also made the message public. Meanwhile, the SOA was preparing for the press conference that followed. The whole country, if not the whole world, was filled with expectation. On the night before the dive, the on-scene headquarters requested that all departments be ready at all times for the favourable weather to come. It was a little past five in the morning when Chief Commander Liu Feng heard a knock at his door. Who could that be? It was so early that it was still dark outside. "Commander, there is a change of weather! The wind is getting stronger!"

Liu Feng could tell from the voice that the visitor was the forecaster Su Bo. He immediately fumbled for his clothes and then opened the door. "No rush. How come?"

"The wind has come earlier than we expected. It is now already force six and the waves are two-metres high. The latest satellite images also show that it will be like this for the coming three to five days." Su Bo's answer was characterized by some timidity because he feared that such changes in the weather would mean abandoning the original plans.

Liu Feng's immediate response was to verify the situation. He ran, as always, to the meteorology screen in the headquarters, only to find that the wind speed was 11.7m/s, sometimes as fast as 14m/s. He then saw the spray on the surface of the sea, an indicator of winds of above force six and waves of over two metres, both stronger than they should be for a sea trial.

Secretary Liu Xincheng soon joined him on the bridge. It was habitual for Liu Xincheng to come to the bridge every morning before anything else to check on the vessel's status. Also concerned about the conditions, Liu Xincheng shared his views with Liu Feng. They agreed to hold an extended session of the headquarters and the Provisional CPC Committee and invited all department leaders and oceanauts to discuss whether to continue the sea trial.

The attendees of the conference found themselves on opposing sides of the argument. One side said, "There is no turning back at this point. We have to do it. Now everyone knows that our aim is the 5,000-metre record. We would be a laughing stock if we cancelled it at the last minute."

"Indeed, we have to consider the impact on our reputation. We cannot be called liars. Besides, we are not functioning in the worst conditions possible. I think we should do it."

But those on the other side argued, "No way! We have to prioritize safety at all times with the respect for science. I know people are eagerly waiting for the attempt but that does not mean we have to do it recklessly!"

"I agree. We are not doing something that is window-dressing, just to look good. We are taking concrete steps to develop a useful manned submersible for the country. I would rather wait than rush in weather like this."

After a long debate, everyone focused attention on the Chief Commander, the Secretary and the leader of the expert group. It was, indeed, a tough decision. In addition to the media coverage that had aroused public interest, the short window of 15 days for the sea trial also meant that the mission might not be completed given the slim possibility of improved weather.

To dive or not to dive? This difficult question constantly pounded the hearts of the commanders in the way that the waves pounded the sides of the ship. This was a test of the courage and vision of the decision-makers.

Liu Feng, Liu Xincheng and Yu Hang exchanged their opinions in a heated discussion before they made up their minds. "With all factors considered, we have decided to cancel today's task. Therefore, I suggest all departments take corresponding measures and the CCTV report team explain the truth about the adverse sea conditions to the public. This is a representation of the value that the manned deep-sea team place on prudence and truth-seeking."

Liu Xincheng went on, "The Provisional CPC Committee fully supports the Chief Commander! Comrades, we step back in order to leap forward. Science requires 100% certainty. When security is at stake, we must win every battle!"

That night, Liu Cigui, Secretary and Director of SOA, and Wang Fei, Deputy Director of SOA and Head of the sea trial leading group in Beijing, used marine satellites to hold a video-conference with the Jiaolong team. Their message was twofold: congratulations to the team on the successful dive and the record of 4,027 metres and best regards to the team members.

Deputy Director Wang Fei, the host of the video-conference, said, "The 5,000-metre sea trial is something that attracts attention to China and to other parts of the world. The SOA and Director Liu, in particular, has shown his attention and care through real actions. He is now on the line and ready to talk before he sets off for a business trip. Now let's welcome Director Liu for a few remarks."

A warm round of applause broke out in the conference room on the mothership. Liu Cigui smiled and waved his hand, "I'm not here to give a speech but to chat. Yesterday I watched the live broadcast of the first dive. Like the rest of the country, I was so inspired. I pay tribute to you all. Is Ye Cong there?"

"Here!"

"Would you share your feelings of being underwater?"

"Sure, Director Liu." On behalf of all the oceanauts of the test trial, Ye Cong shared the experience of the dive. He also promised that they would always be fully prepared and would carry out the next mission using their best skills and under favourable sea conditions.

His description of the low temperatures in the northeast Pacific Ocean triggered concerns from the Director. "Were you cold down there?"

"No, no. That's not what I meant." explained Ye Cong at once, "It is colder than it was in the South China Sea two years ago. But we feel warm thanks to the thermal insulation measures in the cabin. We are fine."

The leader's support came in the way of a short talk that was casual and interesting. The leaders asked if anyone on the ship was unwell, if there were enough vegetables to eat and if they could watch the news on the television. Chief Commander Liu Feng and Secretary Liu Xincheng gave reports and extended their gratitude to the leaders. In all sincerity, Director Liu Cigui said afterwards, "I was informed today that the sea trial would be postponed for a few days due to the bad weather. I know what you are going through so I decided to talk with you. At three in the morning yesterday, I watched the live dive. The repeat, which I watched later, was also very inspiring. You've made history. Last year's record of 3,759 metres, was overtaken by your 4,027 metres yesterday. I was truly delighted to see the three oceanauts walking out of the cabin in high spirits. You deserve my full respect. You have done a good job under the leadership of the Provisional CPC Committee and the on-scene headquarters."

"You have been in the spotlight over the past few days. Internal references from the Xinhua News Agency and from netizens have all given positive feedback. There were questions, such as 'Why are they returning from 4,027 metres, not 5,000 metres?', all of which demonstrate the public's interest. It is now the sixth day since you arrived at the test area. Under the guidance of the Provisional CPC Committee and the headquarters you have become a family that encourage and support each other. It was your full preparation that finally led to the success yesterday. I am looking forward to the second and the third dives, which will mark our ability to reach 5,000 metres and to conduct the scientific expedition. Every dive holds a new meaning."

"I share your excitement but I have to remind you that you have to keep a cool head and maintain high standards in every detail. Determination and confidence are absolutely necessary but patience and scrutiny are also required to ensure a successful sea trial. We talk with you today because Deputy Director Wang Fei and I miss you very much. We also expect that the sea trial will be conducted in accordance with the plan when it meets the security requirements and the vehicle conditions. The sea trial leading group will conform to every decision made by the headquarters on the scene and the SOA Party Committee will also offer you full support. We are highly delighted to see you are all well and in a good state of mind. I send my best regards to all 96 members on board and I offer my special tribute to Professor Yu."

"You are doing something significant. There is a lot to discover in the sea. A better knowledge about the Pacific Ocean, which spreads half way around the world, means a broader understanding of the whole globe. With such information in mind, we can better protect and explore the planet for our wellbeing. Your job is very meaningful in that you are reaching new depths and the whole country is reaching new heights in its familiarity with the sea. We look forward to more good news to come!"

His words, which were so kind and soothing, swept away all the disappointment, confusion and frustration caused by the weather- related delay and provided comfort and encouragement to the whole team.

On 25th July, four days after the original date, the on-scene headquarters seized the break in the strong winds to carry out the 41st Jiaolong diving trial. To make full use of the day, the headquarters and the Provisional CPC Committee decided to bring breakfast forward to 6:20 to make room for a ceremony for Ye Cong, Fu Wentao and Yang Bo prior to the mission. At 7:30, the Chief Commander, Liu Feng, ordered "All in place".

With the Jiaolong gradually being pushed out on the railcar, the A-frame was put in place and the main cable was loaded, accompanied by the run-up work with the hooks and hoist. There was a force-5 strong wind and the waves were 2.5 metres high. The sea, with patches of spray, was rocking the ship harder, leaving it swinging from side to side. At this critical moment, Zhu Min, Director of the Acoustic Department, reported signal intermittence in the synchronic clock. This meant that the ultra-short baseline and the reply machine could not be synchronized, which required immediate checking and fixing on the spot as, otherwise, the headquarters would not be able to receive data on the submersible's position. This was not something that should be taken lightly. On the one hand, it was already difficult to lift the vehicle up and to keep it stable in the air, let alone placing it back onto the railcar. On the other, the dive could not be resumed if the glitch was not dealt with.

Chief Commander Liu Feng then ordered, "Ⅲ-3 (the A-frame operator) drive the submersible back."

"Ⅲ-3 understood", responded Yu Jianxun, Director of the Department of Surface Supporting System, Vice Chief Commander of the sea trial and senior engineer of the 701 Institute.

During repositioning to the block, the Jiaolong's bottom rear stand was damaged in the collision with the railcar, which, fortunately, did not impact the dive. When the problem with the synchronic clock was quickly fixed the headquarters again demanded, "Every department, get ready for the dive."

Hardly had one trouble passed when another arose. Yu Jianxun reported, "The changed sea condition is now beyond the range outlined as appropriate for the sea trial. It is my suggestion that we cancel the trial today."

Headquarters disagreed. Yu Jianxun, whose face paled with anxiety, said, "The wind is too strong and the waves are too high for any test. Compounded by the swings in the air, the trial may be susceptible to accidents. I call for an emergency meeting of the headquarters to discuss the matter."

Yu Jianxun is a senior engineer and a fellow of the 701 Institute of CSIC. A beanpole with a scholar-like appearance, engineer Yu sets a high bar for his work. Under the leadership of Wu Chongjian, Director of the 701 Institute, Yu had participated in the design, R&D and operations of the surface support system since the beginning of the Jiaolong project. From the railcar to the A-frame, he had installed every screw and cable with a passion for his career and dedication to the surface support system. He had attended every sea trial and conducted careful operations that ensured the safe deployment and return of the Jiaolong. Just like his name, he had made contributions to the sea trial.

However, engineer Yu is sometimes too cautious to take risks, a side effect of a strong sense of responsibility. Every night before a sea trial he kept track of the weather reports and checked them with the broadcaster Su Bo. Even so, he still worried about the possibility that deteriorating weather might cause trouble for the sea trials. He was unable to sleep without taking pills prescribed by Doctor Fu Jinling. This was a consequence of his commitment to his job. The rising waves that day, therefore, increased his concern.

Chief Commander Liu Feng eventually agreed to hold an emergency meeting. It took only a few minutes before people from the Provisional CPC Committee, the on-scene headquarters and the expert group were gathered in the conference room. Liu Feng chaired the meeting and briefed the audience before opening the floor for discussion. As the first speaker, Yu Jianxun shared his point of view, "According to the guidance, sea trials can only be conducted when the wind is less than the force 4 and the waves are no higher than two metres. Given the current sea conditions, we cannot ensure the safety of the Jiaolong mission. I think we should cancel today's dive and wait until the weather allows."

Looking at each other, no one could give a definite answer with so much going on in their heads. After a while, everyone began to share their opinions. Some shared engineer Yu's point that the trial should be suspended because the weather was too bad. However, some said that the conditions were much better than the last time. As long as full preparations were made and everything was careful manoeuvred into place, there was no reason that the test could not be a success. The opportunity to win this "battle" may slip through our fingers if there is any further delay. When all views were exchanged, Liu Feng invited Secretary Liu Xincheng to share his view.

"Okay." Liu Xincheng cleared his throat, "We have to base our decision on full knowledge. To begin with, the Pacific Ocean is not our coastal waters where an ideal area for sea trial would be easier to find. Second, the sea conditions, although highly undesirable, are still within the acceptable range. Third, the weather forecast shows that such conditions will continue into the coming days. Fourth, the trial parameters were set before 2009 and due to inexperience, they are more conservative than is necessary. After the 1,000-metre and the 3,000-metre trial, our team is now much better, both in terms of operational skills and compatibility. We should be confident that with our joint intelligence, physical contributions and with careful manoeuvring we can succeed. Therefore, I side with the supporters of the sea trial. If anything goes wrong, the Chief Commander and I will take all the responsibility."

His logical analysis brought light to the confusion and the scale of debate suddenly tilted to those in favour of the dive going ahead. The majority then persuaded Yu Jianxun. "Yu, you should trust our abilities after so many years. We can endure the test this time." "Don't worry. We are always with you."

Such an exchange of opposing views, a common practice of Chief Commander Liu Feng, always preceded any major decision. Views were traded to improve understanding and to reach consensus. Meanwhile, confidence and determination were taking root in the discussion. At the end of the meeting, for the sake of time, Liu Feng explicitly shared his decision. "I totally agree with Secretary Liu Xincheng and the other comrades. We have to have faith in the maturity and capability of our team, in addition to acknowledging the upcoming challenges. Engineer Yu made a lot of sense by warning us of the strict rules we must bear in mind in today's operation. Thus, no oversight is allowed. Without further ado, I give you 15 minutes preparation before resuming the dive."

"We are determined to complete the mission!" The attendees at the meeting, including Yu Jianxun, made the pledge before returning to their posts for the run-up to the trial.

At 9:15 local time, everyone was, once again, in position. Engineer Yu, whose opinion had not been accepted, was in compliance with the headquarters' decision at the meeting. To ensure security and to set an example to his "apprentices" -- Ding Zhongjun, Shi Xianpeng and Li Dewei -- he even took over the job of the main operator in charge of the railcar and the A-frame. Wearing a safety helmet and carrying the operation plate on his back, from the shaking rear deck Yu fixed his eyes on the Jiaolong. Following the orders for positioning and detachment, he pressed the power button and controlled the main cable and yaw-checking devices.

At 9:38, filling with water, the Jiaolong dove into the sea after clearing water surface checks. Thanks to constant observations and the careful operations of the oceanauts, this was a very smooth process. The underwater acoustic communication system was very helpful in uploading all the parameters of the submersible. At 10:21, the vehicle reached 1,000 metres. It then reached 2,000 and 3,000 metres. At 11:40 it broke the previous record, reaching a depth of 4,072 metres. Cheers were about to burst out from the headquarters as the submersible reached 4,992 metres when depth updates failed to deliver communications to the Office of Acoustics Control. People were distressed until the new figures showed up on the screen -- 5,038 metres! The numbers ignited the headquarters!

At 12:17 the number had climbed to 5,057.541 metres, setting a new record for Chinese manned deep-sea diving! We made it! The mothership headquarters and the Office of Acoustic Control were exploding with thunderous cheers and applause. Eyes watering and words choked, Chief Commander Liu Feng and Secretary Liu Xincheng hugged each other. The report group covered the story at the scene. Wang Kaibo even squeaked with excitement, "We are now sending this report from the northeast Pacific Ocean. Just now, at 6:17 Beijing time, the Jiaolong manned submersible overcame the technological challenge by reaching a depth of 5,057 metres. China is thus the fifth country that has achieved such an accomplishment."

Although it was still early morning back home, many people had stayed up for the news. The report brought enthusiasm throughout the country as everyone took pride in the technological breakthrough.

In the hours that followed, the submersible completed all the predetermined missions. It managed to sit on the bottom of the sea, conducted patrols and took and uploaded pictures of the landscape and of a range of species on the seabed. At 15:20 it safely surfaced.

At 16:07 local time, the Jiaolong surfaced. Again, under the well-organized marshal of Yu Jianxun, despite the billows, the workers responsible for surface support managed to safely return the vehicle to the deck after two attempts. At 16:30 a welcome ceremony was held for the oceanauts at the rear deck. Applause and cheers accompanied the oceanauts as they waved to the crowd while stepping out of the cabin. When the three warriors displayed the national flag they had taken to the seabed, everyone was re-excited among lasting applause.

The three men walked down the platform and hugged Liu Feng, Liu Xincheng and Professor Yu below the stairs. Clapping for their teammates, all the staff swarmed towards the three heroes. Even the three kitchen staff in their outfits joined the crowd on deck. They banged ladles, lids, basins and pots together to stir up the excitement, the sound of which was comparable to a symphony. Together, eight people threw the three heroes up into the air.

(selected from Jiaolong's Sea Explorations by Xu Chen, published by China Intercontinental Press in 2019)