Underwater Archaeological Equipment Who is the expert on underwater archaeological process?

● Underwater short baseline? That is, the underwater monitoring and command system, which applies the short baseline sonar system to underwater archaeological practice, is the first time for the archaeological use of Xiaobaijiao No.1 shipwreck in China. In fact, this sonar system can also be said to be a measurement and tracking system, and the geophysical equipment in the water is basically acoustic signals. Two dumbbell-shaped things, hanging underwater on both sides of the cabin, show the activities of underwater archaeologists, which can show the scope and state of personnel activities in real time.

● Suspend the plate with shark-like section in shallow stratum under the water beside the cabin, tow it away by the ship to detect the relics buried below the seabed surface, and transmit the data to the laptop, and analyze the changes of geological structure below the seabed surface according to the echo signal intensity, so as to judge whether there is a sunken ship under the mud.

● Underwater camera? The only difference between underwater camera and land camera is super waterproof. Different from ordinary cameras, underwater cameras are covered with waterproof shells, and recorded short films can be kept as archaeological materials and archives. ?

● Marine magnetometer? Yellow and white instruments are suspended under the hull to detect underwater metal objects according to the principle of the earth's magnetic field. It works a bit like detecting mines on land.

● Differential positioning system? It plays the role of GPS, that is, DGPS, with high accuracy. There is no reference object at sea, so it is difficult for the naked eye to distinguish the exact destination, so this instrument is needed to accurately locate it at sea and on land, with an error of less than one meter.

● Underwater horn? People on the water, if they have any instructions for underwater divers, can convey orders through underwater speakers.

● Oxygen content tester? This time, the underwater archaeologists used high-oxygen diving, and the oxygen concentration was higher than that in normal compressed air. The advantage of this is that the stay time of underwater archaeologists can be appropriately extended.

● Underwater wireless communication system? A way of underwater communication, which can realize three-way communication between underwater and water, underwater and water, without cables.

● Underwater video surveillance? It is convenient for the ship's personnel to monitor the work of underwater archaeologists in real time.

● British L-3? System? 3900 HD side scan sonar system? By transmitting sound to the seabed, the sound waves reflected from the seabed can be judged, and the purpose of detecting the remains of underwater seabed surface geomorphology changes can be achieved.

Experts talk about underwater archaeological process

Fu Yimin is an associate researcher at the Municipal Cultural Relics Protection and Management Office (Archaeological Research Institute) and a participant in the second training course of underwater archaeology in China. During the period of 1999, I participated in the underwater archaeological practice of Bai Jiao shipwreck site in Dinghai, Lianjiang County, Fujian Province. "The Bai Jiao shipwreck in Dinghai is loaded with Fujian black glazed porcelain, which is different from a large number of blue and white porcelain in the Xiaobaijiao No.1 shipwreck." Yesterday, Fu Yimin introduced the working procedures and required equipment of underwater archaeology in Ningbo.

The first task is to find and locate underwater locations.

Fu Yimin said that underwater archaeology and land archaeology have the same principle, but the working environment is different, which requires a lot of modern scientific and technological methods and means.

"This sunken ship has an obvious feature. The remains it forms are generally disposable, and there is no distinction between morning and evening in archaeological strata. The ship's hull, loaded goods and daily necessities reflect the social side at that time and can judge the age and shipping nature. "

Finding and locating underwater locations is the first task. "You can find it by diving and instruments. Dive to find the common floating line, put a long rope on the bottom of the water and tie the buoy in sections. Divers find the target and mark the nearest buoy. There is also circle search. After the land survey, determine the approximate location of the underwater location. Lay a fixed pile on the bottom of the water and tie the rope. The diver tightened the other end of the rope and made a circular search around the fixed pile on the seabed. After returning to the original place, shrink the rope and continue to search in circles. " Fu Yimin told the reporter, "The radius of the circle is generally around 10 meter, because there are undercurrents and tidal bore at the bottom of the water. The underwater visibility of the East China Sea is about 5 meters, which is basically invisible and can only be touched. "

Looking for instruments means looking for modern equipment, including scanning sonar system, shallow seabed profiler, magnetometer and so on. Fu Yimin said: "Modern equipment combined with divers' underwater search is a better method. "

After finding the underwater location, be sure to locate it accurately. "Positioning is to mark the specific location of the site on the chart and mark it with latitude and longitude numbers, so as to quickly find the site in the specific location. There are two main positioning methods: one is to use the reference objects on the shore to locate and match with the landscape photos; The second is instrument positioning, which means precise positioning with GPS. "

The preliminary investigation of underwater archaeology is very important. "The Xiaobaijiao I shipwreck has undergone a large number of shore investigations. Through the information provided by fishermen, the underwater archaeological team determined the scope, nature and value of the site and the underwater environment of the sea area, and learned about the preservation status, articles and burial degree on board, sediment concentration on the seabed, stratum accumulation and so on of Xiaobaijiao No.1 shipwreck. And carried out underwater photography and small-scale excavation. The preliminary work is very complicated. "

"Meiyuan stone is the heaviest, so it finally came out."

For safety and mutual cooperation, underwater archaeological work must be carried out by two people at the same time. "One person digs, and the other person records and measures." Fu Yimin introduced the underwater operation method. "Generally, 2m× 2m exploration method is adopted. Hard exploration is to put a shelf made of metal on the site. The shelf is an exploration that can be used for a long time. The other is soft exploration. " He told reporters that hard exploration is generally used at present because it is more accurate.

Accurate recording, measurement, drawing and photography are the differences between underwater archaeology and general salvage. How do divers communicate underwater? "I used to participate in underwater archaeology, and I could only use certain gestures, such as making a fist and pointing my thumb up to get out of the water. Now, with the underwater wireless communication system, I can realize underwater and underwater three-way communication. " There is also an underwater video surveillance system to control underwater excavation in real time. In addition, underwater photography is also an important recording method, and it is necessary to record the mining objects and the mining process in detail.

When talking about the problem of Shen Bao coming out of the water, Fu Yimin said: "The principle of' getting the goods first, then getting them down, first making it easy, then getting into battle lightly' is followed. Meiyuan stone is the heaviest, so the Xiaobaijiao No.1 shipwreck was extracted and put behind it. " Articles are packed into net bags or cages in batches, lifted out of the water, registered and numbered, and collected after preliminary cleaning.

Underwater operations are most afraid of entanglement.

Fu Yimin introduced personal diving equipment, underwater cameras, underwater wireless communication systems, underwater video surveillance and other major equipment. "The underwater situation is very complicated, especially in the East China Sea. As an underwater archaeologist, you must have a good psychological quality. Don't panic when you are entangled in aquatic plants and fishing nets. Contact your partner in time and cut it off with a diving knife. "

The gas supply equipment for underwater operation includes gas cylinders and surface pipelines. "Compared with gas cylinders, the water supply is humid and it feels much more comfortable." He said that the disadvantage of pipe supply is that the operator's activities are not large, and it is "suitable for underwater fixed-point operations, such as underwater archaeological excavation and small-scale exploration and measurement." Generally, two kinds of gas supply equipment should be prepared.

The excavation equipment is mainly a dredging machine, which "sucks the silt covered on the site and ruins, which is convenient for observation and recording, and is suitable for underwater sites with sand bottom or mud bottom."

Fu Yimin also introduced the work boat and work platform. "According to different sea conditions and different conditions, use different forms of work boats. Work ships can be warships, transport ships, fishing boats, etc. , used to place instruments, equipment, diving equipment, etc. And it can also be used as a work and activity venue for participants, and it also provides convenience for divers to enter and leave the water. "