Sunken Treasure

Few things attract interest in history more than a sunken shipwreck. But the survival of wooden ships underwater is a matter of luck, with oxidization taking its toll and marine organisms capable of eating a vessel completely unless buried under specific geological conditions such as extreme cold or under a covering of silt.

The recent recovery of the wreckage of a merchant ship loaded with exquisite porcelain, has given the world a new opportunity to understand the life and trade of the Chinese people and their business partners 800 years ago.

The 30.4-meter-long and 9.8-meter-wide ship dates back to the early Southern Song Dynasty (1127-1279). The sea bottom where the wreck was found was about 25 meters under water and the ship was covered by silt more than one meter thick. Lying on the sea bottom for such a long time, the ship, named Nanhai No.1, surprisingly had stayed upright. Judging by the porcelain products excavated from it and the direction of the ship head, archaeologists estimated that the vessel was likely to have sunken on its way to Southeastern Asia or the Middle East countries for trade.

The ship's contents cast new light on the development of China's porcelain trade in the Southern Song Dynasty, with tableware was being made particularly to suit the tastes and dinning habits of customers thousands of miles away.

A popular theory among Chinese historians is that since China's Han Dynasty (206 B.C.-220 A.D.) or even earlier, Chinese merchants on the coastal regions had been engaged in shipping porcelain, cloth, silk and probably grain seeds from ports of southern Guangdong Province to India. Then these Chinese goods were sold to people in Egypt and Rome. This trading path has been named the Marine Silk Road, and dates back earlier than the better-known overland Silk Road. Many people nonetheless have doubted the existence of such a trading path due to lack of evidence. The discovery of Nanhai No.1 goes a long way toward proving its existence.

Extremely fragile

Nanhai No.1 has been acknowledged as the largest, oldest and best-preserved shipwreck in China. It also has created another national record as the most expensive excavation project.

After the shipwreck was located in 2001, archaeologists met with enormous difficulty in designing a salvage plan. If they chose the traditional method of first excavating relics piece by piece, then the information on location of items on the ship would be lost forever. Moreover, after being soaked in the water for at least 800 years, the ship's body was extremely fragile. After all the items on it were taken away, an even bigger challenge would be how to lift the ship out of the ocean.

To better protect the wreck and avoid damage during the excavation, experts of Guangdong Provincial Institute of Cultural Relics and Archaeology and Guangzhou Salvage Bureau worked together and creatively suggested using a steel box to hold the wreck and its surrounding silt as they were hoisted out of the water.

Wei Jun, a researcher from Guangdong Provincial Institute of Cultural Relics and Archaeology, said since 2002 the State Administration of Cultural Heritage had conducted four appraisals on the salvage plan, which had been improved over the process. The plan was finally adopted in June 2006 and his institute signed an outsourcing salvage contract with Guangzhou Salvage Bureau in December 2006.

In January 2007, the command center of the salvage mission was set up and the Ministry of Finance allocated 30 million yuan ($4.3 million) for the project, making it China's second most expensive cultural heritage protection project after the renovation of Potala Palace in Lhasa. The same month, Guangzhou Salvage Bureau began to send out salvage expeditions to measure the ship ready for its move. At this preparatory stage, nearly 500 items had been salvaged, including metal items, porcelain, copper coins and broken pieces of lacquer.

To box the ship out, Guangzhou Salvage Bureau manufactured a bottomless steel cage weighing 530 tons that was 35.7 meters long, 14.4 meters wide and 12 meters deep. After the open side of the cage was pushed into the seabed, divers put 36 steel beams across the bottom of the cage to hold the ship. The first beam was placed on September 4. The placement process took much longer than expected due to a particularly hard mud layer and was completed on November 13. Then divers put 37 steel plates, each 12 mm thick, in the gaps between the 36 steal beams, forming a bottom for the cage.

On December 22, the largest floating crane in Asia, Huatianlong, made in China, lifted the steel cage onto a barge. The event was shown live by national broadcaster China Central Television.

Salvage mission

In total, the salvage operation of Nanhai No.1 took Chinese archaeologists 20 years due to suspensions caused by lack of money and technology.

Zhang Wei, founding Director of the Underwater Archaeology Center of China and the lead archaeologist in the Nanhai No.1 excavation mission, has spent most of his professional career exploring the ship since 1987.

Nanhai No.1 has been acknowledged as the largest, oldest and best-preserved shipwreck in China.

Shortly after the founding of the Underwater Archaeology Center of China, an employee of Guangzhou Salvage Bureau told Zhang that the wreck of an ancient ship had been found in the South China Sea in August by a joint search program with a British Company, and the State Administration of Culture Heritage had stopped the salvage operation.

Zhang immediately realized the shipwreck's significance of proving the existence of the Marine Silk Road, but his center then had no personnel or equipment to conduct underwater archaeology.

A Sino-Japanese underwater archaeology team was founded in November 1989, to conduct research on Nanhai No.1. While scuba diving, Zhang for the first time touched the ship deck and the concretions on it. The Japanese side terminated cooperation with the Chinese archaeologists, and Zhang was unable to continue his underwater research due to lack of money and personnel. "A piece of porcelain, a 1-square-meter deck and 30-cm-high concretions," written in a research report, was all that was known about Nanhai No.1 for the next 10 years.

In 2001, when Zhang's underwater archaeology center was granted a fund of HK$1.2 million by the Hong Kong Underwater Archaeology Association, he decided to use the money to explore Nanhai No.1.

But Zhang's team still had great difficulty in locating the wreck. Just as the money was running out, team member Cui Yong found a piece of concretion in the water with some porcelain on it, which confirmed the location of the ship.

In 2002, Zhang's underwater archaeology team was granted a fund of 40 million yuan ($5.7 million) by the Ministry of Finance, which enabled them to collect artifacts from the shipwreck. When they entered the ship in March 2002, they were amazed by what they saw. In a small cabin where thousands of pieces of porcelain piled up, most in perfect condition. They eventually brought 4,000 pieces ashore. "It was really hard to describe my feelings back then," Zhang said. "I wanted to laugh and cry at the same time."

Permanent home

After Nanhai No.1 was hoisted from the bottom of the sea, the barge holding it was dragged to a temporary port before being moved to its new home, the 150-million-yuan ($21.4 million) Marine Silk Road Museum, specially built to exhibit the ship.

A glass pool, named "crystal palace," the permanent home for the ship, will be injected into 12 meters of seawater with the same temperature, pressure and other environmental conditions as the sea where the ship was found. Audiences will be able to observe the ship by walking around the transparent walls of the pool or through a corridor under the pool that gives a view of the underside. It has been estimated that there are still 60,000 to 80,000 relics on board.

Staff members of the museum have been injecting water into the box regularly to keep moisture in the environment. On March 26, the museum started to inject six meters of deep seawater into the glass pool while it was under construction.

The seawater in the pool has been filtered to avoid the entry of marine organisms that might harm the shipwreck. Every day, 10 percent of the water is recycled to ensure its freshness. The new museum is expected to open to public as early as the end of 2008.