The invention of scuba allowed human beings to freely enter the underwater world, and underwater archaeology was born. In the underwater archaeology process of "Nanhai No. 1", we took the overall salvage method and designed a huge steel sinking well to put into the water. Weighing 5,500 tons, Nanhai No. 1 excavated a total of 180,000 sets of cultural relics, as well as more than 130 tons of iron and tens of thousands of copper coins. Nanhai No. 1 is the world's first and the only project in the world, how was it salvaged? What did we unearth from Nanhai One? What is the current status of underwater archaeology in China?
Produced by: Gezhi Dao Pulpit
The following is the transcript of the speech of Cui Yong, deputy director and researcher of the Guangdong Institute of Cultural Relics and Archaeology:
Hello everyone, I am Cui Yong, the project leader of "Nanhai No. 1". Our work is mainly underwater archaeology, moving the work of terrestrial archaeology to do underwater. However, moving archaeological work underwater is not simple, as it is built on the development of engineering and technology.
The birth of underwater archaeology originated from an opportunity, in 1943, the French naval officer Cousteau invented the portable underwater respirator, commonly known as "scuba". Because of the invention of "scuba", human beings can freely enter the underwater world.
Portable underwater breathing apparatus
If you have dived through the water, you know that diving is a very pleasant thing. Due to human exploration of treasures and their own nostalgia, the invention of artificial "scuba" was first applied to ancient shipwrecks.
The general underwater archaeological process is shown in the figure below, which shows the Japanese underwater archaeological work in Syria. Above the picture is a barge, below the picture is the site of the shipwreck, and in the middle of the picture is the work of the archaeologists.
We believe that the ideal state of underwater archaeology should be a water-quality environment, and the underwater archaeology we often do is turbid water archaeology, which is also the characteristic of Chinese underwater archaeology.
Ideal (left) and reality (right)
In the underwater archaeological work of the "Nanhai No. 1", the visibility is only 20 centimeters.
There is a contradiction in archaeological work. The cleaner the water quality, the worse the protection of cultural relics, especially wooden shipwrecks; the worse the water quality, the thicker the stasis, the best protection of cultural relics.
Underwater archaeological work of "Nanhai No. 1"
The best place to protect cultural relics is not museums and exhibition halls, but underground and underwater, and "Nanhai No. 1" is exactly in line with the double insurance of underground and underwater. With this double insurance, our expectations for "Nanhai No. 1" are very high.
The discovery and salvage of "Nanhai No. 1"
The white dot in the image below is the sinking site of Nanhai One.
We discovered the shipwreck in 1987, when I was a lad. Until now, I have been involved in the reception of 247 artifacts. From the discovery in 1987, to the first survey in 1989, to the decision to salvage in 2003, we conducted a total of 8 investigations. In the course of the investigation, we found that the Nanhai-1 was indeed well preserved.
Archaeology needs to collect image data or drawings, but because the archaeological environment of "Nanhai No. 1" is very low visibility, it is impossible to collect image data, so we decided to take the overall salvage method.
"South Lake One" salvage site
We had never tried the overall salvage method before or at home, but after discussion, we decided to take the first step. Before the overall salvage, we must first do an investigation to prepare for the preparation of the salvage plan, the most important of which is to understand how thick the silt buried the ship is. We drilled 30 meters of silt and found that the overall salvage scheme was theoretically feasible.
In 2004, the overall salvage data collection project - 30 meters of mud sample drilling on the seabed
The overall salvage programme was demonstrated four times before and after, and was not officially implemented until 2007. Later, we designed a huge steel sinking shaft, 33 meters long, 14 meters wide and 7 meters high. The picture below is some photos of steel sinking wells, and when they are put underwater, we can't see them.
Steel sinking structure
The scene of the sinking well
It takes 6 steps to put a steel sinkhole into the water. The first step is to position and put it down; the second step is to use cement blocks to press the steel sinking well to the design level; the third step is to excavate the surrounding silt; the fourth step is to cross the 36 bottom beams; the fifth step is to separate the sinking well and lift it; and the sixth step is to float to the surface. These six steps went from April 2007 to December 2007.
After the steel sinking well floats to the surface, you can see the "South China Sea No. 1". In the process of de-laying the steel sinking well, there is a relatively mature technology - pulling, through the airbag pulling to pull the "Nanhai No. 1" from the point to the Yangjiang Guangdong Maritime Silk Road Museum opposite.
Caisson undulation (left) and airbag pull (right)
When salvaging, we still need to think about where to put the wreck later. There is no problem in fishing it, but it still needs to be considered where to put it after fishing. If there is no suitable place to place the shipwreck, it will quickly break down, which is also a kind of destruction.
In 2004, we decided to build a museum. Through design bidding and construction, the foundation stone was laid at the end of 2004 and the construction of the museum was completed in the first half of 2007, which is the home of the "Nanhai One".
How much does the "Nanhai No. 1" have to be fished from the bottom of the water? Together with the weight of the hull, cargo, mud and caisson itself, the total is 5500 tons.
At that time, the largest crane ship in China was at the Guangzhou Salvage Bureau, and its lifting capacity was 4,000 tons. At that time, this crane was the first crane in Asia and the sixth crane in the world. Now we have 10,000 tons of cranes, which should be used to build the Hong Kong-Zhuhai-Macao Bridge.
Because the shipwreck is heavier, we can only lift it out of the seabed, but not out of the water. We used another 16,000-ton submersible, an engineering submarine, to sink down. Then put the gondola on top of the submerged barge, and then drain the water from the submerged barge to float it, and at the same time use the gondola to hang it, and through the addition of these two forces, we drag the "South China Sea One" to the side of the Crystal Palace.
But the museum is still more than 400 meters away from the sea, how to pull more than 5500 tons of things from the sea into the museum's Crystal Palace?
We took a stupid approach. We paved the way, using the ancient method of moving the weight of the roller, putting some rollers under the weight, pushing it, and then moving the back of the roller to the front, so that the weight could be moved forward.
But this caisson was too heavy for rollers to be possible, so we used airbags. We prepared 16 airbags as rollers, and cushioned the airbags under the wreck, each of which had a load of 400 tons, and 16 were just 6400 tons, far exceeding the weight of the "South China Sea One".
It was by using the method of rolling wood to transfer weight, inflating the airbag exhaust, and finally on December 28, 2007, we dragged the "Nanhai No. 1" into the museum.
Shipwreck successfully salvaged and towed to the museum (left), museum waiting for the wreck to enter (center) and shipwreck towed into the "Crystal Palace" (right)
Entering the museum, we immediately sealed the wall and filled the sea water, so that the shipwreck was in a state of original ecological protection, and would not be damaged and deformed, which was the best way to protect it.
Shipwrecks are a huge treasure trove
After the "South China Sea One" is placed in the Crystal Palace, we will excavate it.
Archaeological excavation of "Nanhai No. 1" in 2009
In 2009 and 2011 we conducted a trial excavation each to try to find the best way to excavate. The only way to find the last thing is to keep the water digging, that is, to put a little water to dig a little.
Since the excavations, the orthophoto image of the "Nanhai No. 1" site has changed
The results of the excavation now show that this program is very successful. Since 2014, digging until June 2019, we have cleared the cargo of this shipwreck, a total of 180,000 sets of cultural relics. The 180,000 sets of cultural relics are only ceramic things, and do not contain more than 130 tons of iron and tens of thousands of copper coins.
Ceramic artifacts
Since its establishment in 1959, the total collection of the Guangdong Provincial Museum is 180,000. The amount of cultural relics of the "Nanhai No. 1" has exceeded the total collection of the Guangdong Provincial Museum for 60 years, so the shipwreck is a huge treasure trove.
The Nanhai One is a huge treasure trove
No one used to know how ships from 800 years ago were loaded, but now we show the public. The picture below shows the very beautiful Longquan porcelain excavated from the shipwreck, the thin tire blue glazed porcelain of Jingdezhen and a large amount of gold jewelry, and we found 2.8 kilograms of gold and more than 300 kilograms of silver.
Longquan porcelain
Thin-tire blue glazed porcelain from Jingdezhen
Gold jewelry dug out of "Nanhai No. 1"
The silver ingot in the figure below is the standard weight of 25 taels, engraved on it, and we can reverse the ancient weights and measures through the silver ingot.
Silver ingots
We also dug up jade, Guanyin, Arhat, and many bronze artifacts in the wreck.
In particular, the first bronze in the upper left corner of the picture below and the weighing pan and weights below the bronze ware are also exhibited in the Saudi Museum, indicating that the "South China Sea No. 1" and the Arabs at that time had exchanges. Later excavations in port Sellin also found this weight.
During the excavation, we also found something very magical - salted duck eggs, and we found a lot of cans.
Salted duck eggs excavated in "Nanhai No. 1"
A shipwreck is a time capsule that sinks to the bottom of the water in a short period of time, and it holds all the time inside.
There are many people on board, and they need to ensure the basic survival from the captain to the general crew to the sailors in a time unit, which is the smallest survival unit and the smallest hierarchical society.
Some people may wonder, what is the most representative thing among the 180,000 cultural relics of "South Lake One"?
It's a hard question to answer, but I can set a standard. The first criterion is uniqueness, which has only one thing. The second criterion, which is definitely not something commonly used, must be a work of art. The third criterion, which can reflect the aesthetic taste of people for this work of art at that time.
First of all, looking for the only one, I found the conch carving cup, which is made of luminous salamander. Luminous salamander snails are produced in the South China Sea, and they are also found in Taiwan and Japan. A luminous salop is cut in half, then polished, and carved on the glossy surface of the saloon, carved into peony flowers.
Because this salamander is only one piece, I was worried that others would damage it when they watched it, so I made a three-dimensional collection of this conch carving cup, which allowed the viewer to see the three-dimensional presentation on the computer.
Three-dimensional presentation of conch carving cup (left) and conch carving cup (right)
Later I discovered a peculiarity, this conch carving cup has five holes in three dimensions, like the Maritime Silk Road Museum. The Maritime Silk Road Museum was designed in 2004 and the salamander was discovered in 2014. Although the museum was designed first, and then the salamander was found, the museum seemed to be built according to the salamander, which was the fate of 800 years in the underworld.
I know the designer of the museum, he is the son-in-law of Academician He Jingtang, his name is Xian Jianxiong. When I showed him the salamander, he was so excited that he wanted to prototype the design from the skeleton of a sea creature, but I didn't expect to restore it.
Snails travel with houses on their backs, and so do conchs. Now that the museum is built, this museum is the home of "Nanhai No. 1", and "Nanhai No. 1" has also arrived home. Luckily, it wasn't shipped out. If shipped out, the essence of this batch of Chinese cultural relics will be diluted to all corners of the world, and it will not be found.
Current status of underwater archaeology in China
I started with the "Nanhai No. 1" and worked with the "Nanhai No. 1" for 32 years, and I feel very lucky to complete this archaeological work when I am about to retire.
China's underwater archaeology, although it started very late, is currently in a leading position in the world. At present, "Nanhai No. 1" is not only the world's first, but also the world's only project, or the world's UNESCO highly respected project, and it is also mentioned in the Convention on the Protection of Underwater Cultural Heritage.
The "Nanhai No. 1" project includes overall salvage, off-site protection, fine excavation, public display, etc., and the government has also put it on the express train of "cultural stage and economic singing". At that time, the "Nanhai No. 1" Museum was the first modern building in the area, and now it is a city.
There are also many highlights of our underwater archaeology, such as the preservation of the original site of "Nan'ao No. 1" and the Baiheliang Underwater Museum in Fuling, Chongqing. At that time, the United Nations pushed forward two Projects in China, one is the Underwater Museum, and the other is the "South China Sea One".
Baiheliang Underwater Museum in Fuling, Chongqing
The Baiheliang Underwater Museum in Fuling, Chongqing, is another classic of China's underwater cultural heritage protection, and the general public can visit the museum through a tunnel of more than 80 meters to the bottom of the water, and can also see the White Crane Liang stone stele soaking underwater.
When we were working on the "South Australia One" project, we used a huge framework to protect the original site of the shipwreck.
"South Australia One" protected by the original site
There is also a working method of underwater archaeology, using a cofferdam to surround the shipwreck, pumping the water in the middle, and then carrying out land excavations. Pictured below is another archaeological site, Eguchi Shenyin. The average land excavation is about 400 to 500 square meters, while the Jiangkou Sinking Silver enclosure is 113,000 square meters, which is far more than the world's cases of shipwrecks excavated by cofferdam technology combined.
Cofferdam excavation of "Jiangkou Sinking Silver"
Jiangkou Shenyin refers to the fact that Zhang Xianzhong, the leader of the Great Western Army at that time, had sunk silver here. This is the only case of turning treasure into reality, with more than 42,000 pieces of gold and silver treasure unearthed.
The highest state of archaeology is the protection of cultural relics with minimal intervention. We went to the Site of the Shiyan Rock Underwater Mine in Xiqiao Mountain to investigate, because it was a good mine in itself, so we didn't move anything. The protection of cultural relics with minimal intervention is the highest state of archaeology.
Site of an underwater mine pit in Shiyan rock, Xiqiao Mountain
A passage full of finished products
This is also a project I recently did, and now it has entered the eighth batch of national cultural relics protection units. In the picture is a passage full of stones, diving through this passage, there is a feeling of traveling back to ancient times, so underwater archaeology is very worth exploring.
May China have more world firsts! This concludes my sharing, thank you!
"Gezhi Theory Dao", formerly known as "SELF Gezhi Discourse", is a scientific and cultural forum launched by the Chinese Academy of Sciences, jointly sponsored by the Computer Network Information Center of the Chinese Academy of Sciences and the Science Communication Bureau of the Chinese Academy of Sciences, and hosted by the China Science Popularization Expo. Committed to the cross-border dissemination of extraordinary ideas, it aims to explore the development of science and technology, education, life and future in the spirit of "gewu zhizhi". Get more information. This article is produced from the "Gezhi Dao Pulpit" public account (SELFtalks), please indicate the source of the public account, unauthorized reprint.