The ancient shipwreck "Yangtze River Estuary No. 2" carried a large amount of porcelain. (Source: Shanghai Municipal Bureau of Cultural Heritage)
"Caisson static pressure arbitrage" technology At 11:00 a.m. on December 22, 2007, the "Nanhai I" finally came out of the water in the Yangjiang River area of Guangdong Province, after more than 800 years of sleeping on the seabed. The overall salvage scheme adopted this time is: the shipwreck hull and the shipboard cultural relics and the surrounding sediment are fixed in a special steel caisson according to the original state, and the scattered and fragile cultural relics are integrated, suspended and transported at one time, and then relocated to the exhibition hall for scientific excavation. (Source: Guangdong Maritime Silk Road Museum website)
"Arc beam non-contact cultural relics overall salvage" technology On January 26, 2022, the Shanghai Salvage Bureau conducted a proportional test of the "Yangtze River Estuary No. 2" overall relocation project. When salvaging, the operator will drive 22 giant "arc beams" with the top launcher frame to form a huge arc-shaped caisson at the bottom of the "Yangtze River Estuary No. 2" ship, the caisson is 51 meters long, 19 meters wide and 9 meters high, which can wrap the "Yangtze River Estuary No. 2" and its attached thick sediment and seawater, plus the weight of the salvage equipment itself, the total weight of the caisson is nearly 10,000 tons. (Source: Shanghai Municipal Bureau of Cultural Heritage)
The hull wood salvaged during the "Yangtze River Estuary-2" trial salvage phase has been continuously monitored by archaeologists for several years. (Source: Shangguan News Network)
"Yangtze River Estuary No. 2" and "Yangtze River Estuary No. 1"
The ancient shipwreck "Yangtze River Estuary No. 2" was discovered in 2015. It is located underwater in the hengsha shoal northeast of Chongming Hengsha Island in Shanghai. The ship is about 38.5 meters long and 7.8 meters wide in the middle, and has 31 cabins.
Archaeological investigation shows that the "Yangtze River Estuary No. 2" is a wooden sailing ship, confirmed to be dated to the Tongzhi period of the Qing Dynasty (1862-1875 AD), and the ship type is suspected to be a flat-bottomed sand boat in the Ming and Qing dynasties.
The waters where the shipwreck is located are 8 to 10 meters deep. As of now, the hull has tilted about 27° to the left laterally and is covered with 5.5 metres of silt. The deep silt helps protect shipwrecks from natural and man-made erosion, but many shipwrecks are doomed to disintegration under the long-term influence of gravity and currents. Fortunately, the upper part of the "Yangtze River Estuary No. 2" has a complete structure such as the pointed bow, pile, main mast, left and right sides, and upper deck.
Through the small cleaning of the four cabins in front and behind, it was found that there were exquisite cultural relics such as Jingdezhen kiln porcelain stacked neatly in each cabin. There are many types and quantities of cultural relics that have been completely or restored. In addition, a large number of cultural relics such as purple sand ware, hookah canisters from Vietnam, wooden bucket fragments, masts, large hardwood ship timber, iron anchors, brown cables, pulleys, metal drill bits, drill pipes and black minerals have been unearthed in and around the hull. In particular, the "Tongzhi Year System" section of the bottom book of some water porcelain in the ship provides an important basis for the dating of ancient ships.
After more than 6 years of underwater archaeological surveys and explorations, archaeologists believe that the "Yangtze River Estuary No. 2" is very similar to a flat-bottomed sand ship. This type of boat was widely used in local water transportation in Shanghai during the Ming and Qing dynasties.
The salvage was carried out this time by the "Yangtze River Estuary No. 2", and where is the "Yangtze River Estuary No. 1"?
Since 2011, the Shanghai Municipal Bureau of Cultural Heritage has launched a census of underwater cultural heritage. In 2015, underwater archaeologists discovered a relatively well-preserved iron shipwreck in the Chongming Hengsha waters of the Yangtze River estuary, and its archaeological number is "Yangtze River Estuary No. 1". After underwater archaeological investigation, it was confirmed that the shipwreck was an iron warship of the Republic of China period. Subsequently, archaeologists expanded the scope of surveying and exploration, and found another large and well-preserved shipwreck in the north of the iron warship, the archaeological number is "Yangtze River Mouth No. 2", that is, the wooden ancient ship that is expected to be salvaged as a whole.
Every week, a researcher comes to Chongming to see "wood"
On the stele gallery of the Chongming District Museum in Shanghai, there is still a sink with a dried piece of wood on which traces of shellfish attachment can be identified. This is a hull wood salvaged during the "Yangtze River Estuary No. 2" trial salvage stage. It has been "hosted" here since December 22, 2016. Entering March 2022, this large hull relic, which was the first to come out of the water, attracted people's attention again.
According to media reports, after the archaeological team discovered the "Yangtze River Mouth No. 2" that year, it was urgent to find a place in shanghai where wooden components could be placed for trial salvage. The Chongming District Museum site is large and can meet the conditions for scientific and technological protection, so it was selected.
It is not a simple "wood", and the Chongming District Museum is not a simple temporary "warehouse" of cultural relics, they are scientific research experiments for the long-term protection of the "Yangtze River Estuary No. 2" after the water.
Since then, every week, a researcher has rushed from downtown Shanghai to Chongming to observe the state of the wood, record and save data, and provide scientific research support for future protection and restoration.
When first salvaged from the sea, the "wood" is highly salty and cannot be exposed directly in a dry environment. To this end, the Chongming District Museum has re-established the water storage environment in the monument corridor and regularly changed the water. The salt replacement process lasted for a year. Monitoring the process and speed of air drying is also a scientific research content; due to the fear of biological destruction such as termites, staff have to check every day whether there are new organisms coming to "nest and build nests".
These continuous, uninterrupted scientific conservation studies provide data support for the overall salvage and conservation program. With the progress of the archaeological display of "Yangtze River Estuary No. 2", this wooden component relics will be re-located in "Yangtze River Estuary No. 2".
From "Nanhai I" to "Yangtze River Estuary No. 2"
In December 2007, the famous "Nanhai I" was successfully salvaged as a whole. In October 2021, "Yangtze River Estuary No. 2" was listed as a major project in underwater archaeology in China and is expected to be completed in 2022. This is the second time after 15 years that China has carried out an overall salvage of underwater ancient shipwrecks.
In recent years, underwater archaeological surveys have shown that the "Yangtze River Estuary No. 2" has been seriously washed by the current, especially with the change of the flow direction of the Yangtze River estuary, resulting in the acceleration of the ancient ship to expose the surface of the riverbed, and the hull of the ship is facing a serious safety threat. In order to prevent the natural and man-made destruction of ancient ships, it is necessary to salvage the water as soon as possible and move it into a fixed place to enter the later stage of scientific research.
From "Nanhai I" to "Yangtze River Estuary No. 2", its archaeological excavation, cultural relics protection, research and display and utilization ideas are roughly the same, which can be seen in the development context of the scale and level of Underwater Archaeology in China.
The overall salvage technology applied to the "Yangtze River Estuary No. 2" has been innovated. At that time, "Nanhai I" used the "caisson static pressure sleeve extraction" method, which was a brave attempt and success in the world at that time; by 2022, the Shanghai scientific research and archaeology team adopted an unprecedented scheme - "arc beam non-contact cultural relics overall salvage technology". Both salvages are aimed at maximizing the integrity of the underwater cultural heritage.
According to the salvage plan, once the "Yangtze River Estuary No. 2" is salvaged, it will be quickly lifted to a salvage engineering vessel tailored for the caisson, with a central opening, and then sailed to Dock 1, the former site of the Shanghai Shipyard in Yangpu Riverside, Shanghai.
Shanghai is an important port on the Maritime Silk Road. Today, the "Nanhai I. Museum" located in Yangjiang, Guangdong Province, has become the "Guangdong Maritime Silk Road Museum". The Shanghai Municipal Party Committee and Municipal Government have officially decided to choose the site of the Yangpu Binjiang Shanghai Shipyard, using two old docks and preserved historical buildings to prepare for the construction of the "Yangtze River Estuary No. 2 Ancient Ship Museum", which is also included in the "14th Five-Year Plan" Shanghai Major Public Cultural and Sports Facilities Construction Project. These thematic museums of underwater archaeology will provide a platform for the world to understand the history of the Maritime Silk Road by displaying a comprehensive and long-lasting archaeological research process.
Salvage time capsules
How should we pay attention to the whole process of underwater archaeology, and why should we pay special attention to the "Nanhai I" and "Yangtze River Estuary No. 2"? If people's eyes are still fixed on the huge amount of cultural relics and treasures in the water, it will undoubtedly one-sidedly underestimate its historical, artistic and technological value. The uniqueness of these shipwrecks is that the ancients solidified and "preserved" a figurative social form through tragic forms; today's overall salvage of them is to hope to present a historical moment again almost unscathed. From this we get a "time capsule" that spans history.
The Nanhai I is the oldest, most completely preserved and largest ocean-going cargo ship with the largest cultural relics in China's archaeological discoveries so far. Experts have jammed the historical space-time section shown by this "time capsule" in 1183 AD. More than 180,000 artifacts on the ship reflect the achievements of shipbuilding, navigation, porcelain making, metallurgy, winemaking, textile, carving, lacquered wood making and jewelry processing. Now people can understand the level of science, technology, culture and art during the Southern Song Dynasty 800 years ago. At the same time, the "Nanhai I. as the smallest survival unit, found a large number of animal and plant remains, in the wine jar detected the traces of winemaking, the detection of special silt found the residue of silk protein, these cultural relics evidence intertwined, objectively revealed the crew's food structure and living conditions. More importantly, the most prosperous stage of China's maritime trade can thus be shown in kind.
What we see from the "Nanhai I" and "Yangtze River Estuary No. 2" is unimaginable to China's underwater archaeology 40 years ago when it was just starting out. Under the strong support of scientific and technological strength and social cooperation, dazzling cultural relics are superimposed with the rigorous excavation process and scientific research judgments of archaeologists, telling the world one true and credible Chinese story after another. (Reporter Qi Xin)