The ancient ship "Yangtze River Estuary No. 2" entered the dock! Why do experts speculate that it is a sand ship?

The ancient ship "Yangtze River Estuary No. 2" entered the dock successfully! Four days after the ancient ship "Yangtze River Estuary No. 2" was successfully salvaged, on November 25, the "Yangtze River Estuary No. 2" ancient ship salvage engineering ship "Fenli Lun" embraced the ancient ship and slowly sailed along the Huangpu River into the No. 1 Dock of the former site of the Shanghai Shipyard located on the Yangpu Riverside, and "settled" on the bank of the Huangpu River.

After more than 150 years, the ancient ship saw the light of day again, but with it came a series of puzzles and suspense.

Follow Ye Chong, deputy researcher at the China Maritime Museum, to uncover the possible ship type, naming purpose and technical characteristics of the "Yangtze River Estuary No. 2" ancient ship!

Unveiling the secrets of the ancient ship "Yangtze River Estuary No. 2"

After underwater exploration, archaeologists confirmed that the "Yangtze River Estuary No. 2" is an ancient ship from the Tongzhi period of the Qing Dynasty (1862-1874) . It is about 38.1 meters long and 9.9 meters wide. The bottom of the hull is relatively flat, and there is no obvious keel protruding from the bottom of the ship. Based on the current underwater exploration information, it is preliminarily judged that the "Yangtze River Estuary No. 2" may be a sand ship . However, the final judgment of the type of ship of the Yangtze River Estuary No. 2 requires the ancient ship to disclose more information during the archaeological excavation process.

What are the major types of ships in ancient China?

Ancient Chinese ships evolved from canoes to wooden plank boats and sailing boats. With the expansion of China's water transport and navigation, they gradually explored, innovated and optimized in terms of large-scale, specialized and diversified ships. It can be said that ancient Chinese ships were formed in different ship types after a long period of accumulation of ideas and designs and revisions in navigation practice during the long history of shipbuilding and use.

There are two main views in the academic community about the traditional ship types along the coast of ancient China. One view , based on Ming Dynasty documents, proposes three major ship types: sand ship, Fu ship, and Guang ship ; the other view is that Zhejiang ship should be added to the three major ship types, that is, sand ship, Zhejiang ship, Fu ship, and Guang ship .

A five-masted Shandong ship found in Shanghai

(Source: National Maritime Museum, UK)

The restored Zhejiang sea-going ship "Green Eyebrow"

A Fuchuan-type seagoing vessel departing from Xiamen Port in the Qing Dynasty

The Guangzhou-type seagoing vessel "Jinhuaxing" (Source: Chen Liqun)

So, how do we distinguish these major types of ships? We can roughly examine them from two major categories and seven aspects.

First, the historical evolution of ship types is examined, that is, the origin, development, and standardization of different ship types are mainly examined.

Secondly, the appearance characteristics of the ship are examined, mainly in six aspects, including: the structure and shape of the bottom from bow to stern; the shape and characteristics of the bow; the shape and characteristics of the stern, especially the type and installation of the rudder structure; the characteristics of the sail system; the configuration of tools and accessories; and the differences in paint and decoration.

The reasons for the formation of various and diverse ship types are mainly due to three aspects:

The first is the historical evolution of the ship type system. Ancient Chinese ships developed in the course of the development of water transport and navigation. Therefore, no matter which type of ship, there is a historical process of its origin, development, finalization and later changes. For example, the Fuchuan type seagoing ship of the Song, Yuan and Ming dynasties changed in some aspects when it developed into the Qing Dynasty.

Second, the influence of regional natural geographical conditions on ship types. The design, construction, use and maintenance of ancient Chinese ships are all regional. Therefore, the natural geographical conditions of the main production areas and waters of the ship type have an impact on the design of the ship type, such as the resources such as wood species in the production area and the climate, wind, reefs, currents and surges in the main waters used by the ship. For example, the design of sand ships must take into account sailing on sand, landing on beaches and wading. For example, Guangdong ships mostly use hard wood.

The third is the impact of technology, society, culture, etc. on ship types. Fundamentally speaking, the construction and use of ancient Chinese ships was to meet the needs of shipbuilders and ship users. These craftsmen and boat people, who belonged to the water tribe and had a sea-oriented gene, based on their experience, cognition, customs, habits and even the needs of the humanistic spirit in the field of production and life, also led to the formation of their own distinctive characteristics in the design and layout of different ship types, such as the "longevity hole" with seven stars and a moon on the keel of the Fu ship, and the rich patterns and bright paint on some Zhejiang ships.

In short, the factors at the above three levels have endowed ancient Chinese ships with a strong Chinese characteristic, although they have many types of ships but form their own system. Therefore, foreign scholars specifically call them "Chinese sailing ships" in the history of world shipbuilding .

Why are sand ships named so? What are their distribution and uses?

The sand ship originated in the Yangtze River estuary and Chongming area. It was developed on the basis of a flat-bottomed wooden boat. It can be used on rivers and seas and is a very ancient traditional ship type among ancient Chinese ships.

Judging from the naming method of ancient Chinese ships, the Sand Ship was named after the outstanding performance characteristics of the ship, and the performance characteristics came from the geographical features of Chongming Island.

The Jishi of Rizhilu states that "the sand ships from the south of the Yangtze River that go to Shandong rely on the sand to sail and anchor. The ships have a flat bottom and can run aground easily." Xie Zhanren, a sea merchant in the Qing Dynasty, wrote in Xingchuan Tiyao that "the sea ships from the south of the Yangtze River are called sand ships because they have a flat and wide bottom and can sail and anchor on the sand surface. They can run aground easily. They often make a living by selling crabs from Shagang to Huai'an, so they are very familiar with the shallowness and depth of the sand veins. Shagang is a deep ditch in the sand." Therefore, the "sha" in sand ship can be interpreted as this kind of ship can sail and anchor on sand, and is most skilled in sailing in sand vein waters.

The Chronicles of Chongming County in Qianlong's reign said that "the sand ship got its name from the Chongming Sand", and also said that "Chong was first built with the name of Sand, so most places are called Sand until now". As early as the Wude period of the Tang Dynasty (618-626), the Yangtze River estuary rose to the East Sand and the West Sand, which were the origin of Chongming Island; in the Wu Zetian period of the Tang Dynasty, fishermen and woodcutters began to go to the island to open up wasteland for fishing and hunting; in the Northern Song Dynasty, new sandbanks appeared, and people called this place "Sansha". Many documents call this place "Shadi" and the people here "Shamin". For example, the General Chronicles of Shandong in Yongzheng's reign said that "Shamin grew up on the seashore, were familiar with water, ... so the ship was called Shachuan". Therefore, the "Sha" in Shachuan can also be interpreted as this kind of ship is a ship from the sand land, and is a ship used by Shamin.

According to research, the name "Shachuan" first appeared in the eighth year of Jiajing in the Ming Dynasty (1529). The "anti-sand flat-bottomed" warships in the Jianghuai area in the lower reaches of the Yangtze River recorded in "Song History·Military Records" may be the ancestor of Shachuan. The "flat-bottomed boats" built and tested by Zhu Qing, Zhang Xuan and Luo Bi, the general manager of Shanghai Shipping in the Yuan Dynasty in Shanghai and other places should be the prototype of the later Shachuan, which is also called "Jiangsu trade ship" in modern times.

Drawing of a Jiangsu trading ship drawn by the British during the Republic of China period

(Source: "Sailing Boats and Sampans on the Yangtze River" by Ha Shide)

Historically, sand ships were mainly produced in Chongming, and can be found in Taicang, Tongzhou, Haimen, Jiangyin, Changshu, Jiading, Songjiang and other places. They are suitable for navigating inland shallow waterways and near-shore routes with many sand veins and shoals north of the Yangtze River estuary. In China, they are mainly found in Liaoning, Tianjin, Shandong, Jiangsu, Shanghai, Anhui, Zhejiang, Jiangxi, Hubei, Hunan and other regions. They are widely used as grain ships, warships, merchant ships, fishing boats, etc. For example, the navy of the Qing Dynasty generally used sand ships as warships in important waterway towns in Jiangsu, Zhejiang, Jiangxi, Hubei and Shandong.

A Nanjing ship depicted in the Tang Ship Map

(Source: Ohta Osamu's "Research on Tang Ship Map")

In addition to domestic river and sea routes, sand ships can also sail on the ocean and are seen on ocean routes. For example, the "Tang Ship Map" drawn by the Japanese records and depicts Chinese merchant ships from the southeast coast of China to the port of Nagasaki, Japan in the late Ming and early Qing dynasties. Among them are sand ship-type "Nanjing ships". The length of this sand ship-type sea ship sailing to Japan is even close to 70 meters. According to the British Ivon Arthur Donnelly (1890-1951) in his 1924 publication "Chinese Junks and Other Native Craft" when recording the "Pechili Trader":

As late as 1903, this typical Chinese merchant ship still appeared regularly in Singapore Port. These ships were large, 140 to 180 feet long (note: 42 to 54 meters), 20 to 30 feet wide (note: 6 to 9 meters), and had a carrying capacity of about 4,000 to 6,000 dan (note: 280 to 420 tons). ... Each ship had a crew of 22 to 30 people. ... Although this ship was built in Shanghai, its registered port was Yingkou, ... This ship usually had five masts.

Donnelly in Chinese Junks and Local Ship Types

Sketch of merchant ships sailing to northern Zhili

Northern Zhili Merchant Shipping Line Map

The Chinese sand ship pattern on the Singapore 1 SGD issued from 1984 to 1999

In the early and middle Qing Dynasty, when Xiamen Port's ocean trade flourished, the large "merchant ships" (mainly engaged in domestic coastal trade) in Xiamen Port had a carrying capacity of 6,000 to 7,000 dan, and the large "foreign ships" had a carrying capacity of up to 10,000 to 12,000 dan. Bao Shichen of the Qing Dynasty said in "On the Maritime Transport of Southern Canal" that during the Jiaqing period, "about 3,500 to 6,000 sand ships gathered in Shanghai, and the large ships carried 3,000 dan (note: about 210 tons), and the small ones carried 1,500 to 600 dan." The merchant ships of Northern Zhili were sand ship-type seagoing ships. If Donnelly's record is true, then in the late Qing Dynasty, when Western ships seriously impacted China's traditional wooden sailing ships sailing on the ocean routes, the large sand ship-type merchant ships heading to Southeast Asia had a carrying capacity close to that of the large merchant ships in Xiamen Port in the early and middle Qing Dynasty, but exceeded the large sand ships moored in Shanghai during the Jiaqing period.

From this, we can see that sand ships have a long history, a wide range of uses, and a large number of them. They have a particularly important significance and position in the history of shipbuilding, naval history, maritime transportation history, and commercial economic history in China and even the world. For Shanghai, sand ships have even more special significance in the history of the city, shipping history, and port history.

What are the distinctive features of sand ships?

Among China's four major coastal ship types, the sand ship has a long history, superior performance, and is extremely representative in terms of technical characteristics. Some people even believe that the sand ship is "China's most representative traditional boat."

According to its main navigation waters and functional requirements, the sand ship needs to have outstanding capabilities of sailing on sand, landing on beaches, and wading. This determines some significant features of the sand ship in terms of design and layout, mainly including:

Tiger Eel Sand Ship - Photo provided by Qi Gang

(Photo taken around 1980 or 1981)

Model of a sand ship-type Northern Zhili merchant ship collected by the Science Museum in London, UK

First, judging from the shape and design of the bottom of the ship, the most notable features of the sand ship are its flat bottom and shallow draft.

When a sand ship suddenly encounters quicksand in the shallow sea or the tide recedes, it can use its wide flat bottom, fusiform flat keel, closely spaced transverse bulkhead structure, etc. to balance and safely sit on the shallow sea beach. However, a pointed-bottom seagoing ship will be in a dilemma when encountering such a situation. Once it runs aground on the sand, it is very easy to capsize.

According to the "Discussion on Sea Transportation of Southern Canal", a large sand ship that can carry 3,000 dan (about 210 tons) of cargo has a draft of only 4 to 5 feet (about 1.3 to 1.6 meters). The sand ship has a shallow draft, and with its flat bottom and elevators, it can sail in shallow waters and shallow sea sand veins.

In addition, sand ships are relatively safe in complex winds and waves, especially when the wind and tide directions are different. Because of their flat bottom and shallow draft, they are less affected by the tide and are relatively safe. Wang Zaijin of the Ming Dynasty recorded in "Summary of Coastal Defense": "There are rolling waves in the North Sea. Fuzhou ships and Cangshan ships are most afraid of these waves, but sand ships are not afraid of them."

Second, judging from the structure of the bottom of the ship, sand ships usually use a flat fusiform keel.

The bottom of a sand ship usually uses several thick plates to form a flat fusiform keel that is narrow at both ends and wide in the middle, also known as a "flat keel" or "center bottom". When laying on sand, the sand ship can bear the weight of the hull; when wading, it can withstand the friction of the shallows.

Third, judging from the frame structure of the main hull, sand ships usually adopt a closely spaced transverse bulkhead structure to form more cabins.

The close-spaced transverse bulkhead structure enables shipbuilders to control the hull lines in an era without blueprints, facilitating construction. More importantly, this structure can strengthen the longitudinal strength of the ship and reduce distortion when the sand ship is moored on the sand and loaded and unloaded at low tide, or when it is repaired on the sand without a shipyard or dock. According to research, the 70-foot (about 22.4 meters) sand ship in the Qing Dynasty had 26 cabins, with an average spacing of 0.86 meters between transverse bulkheads. The Yangtze River Estuary No. 2 shipwreck has been found to have 31 cabins, with a spacing of about 0.8 to 1 meter between bulkheads.

Fourth, judging from the shape of the top of the transverse bulkhead, sand ships usually use a beam arch.

The beam arch is the arch height of the top of the transverse bulkhead, which generally decreases gradually from the highest point of the arch on the longitudinal centerline to the edges of both sides.

The height of the beam arch of a sand ship is about 2/5 of the depth, which is about 16% of the ship width. Generally, the beam arch height of a 60-ton sand ship is nearly 0.5 meters. According to the characteristics of the sand ship, the design of the sand ship adopts a large beam arch, mainly for the following reasons:

Firstly, due to the use of a large beam arch, the sand ship lays a movable flat deck on the main deck. The flat deck can protect the main deck, effectively expand the deck operating area, and allow the catch to be pushed flatly into the cabin.

Secondly, the sand ship has a small depth and low freeboard, so the deck is easily caught in the waves when sailing in wind and waves. The large beam arch design forms an air layer between the flush deck and the main deck, which makes it easy for the wind and waves or rainwater on the flush deck to leak to the main deck and be quickly discharged overboard.

Third, sand ships are flat and shallow, and use large beam arches. With a small draft, they can effectively expand the cabin capacity, increase reserve buoyancy, and improve anti-sinking capabilities.

Fourthly, the use of a large beam arch can make the side longitudinal material (da ya) on a shallow-draft ship closer to the water surface. The da ya can act as a fender. When adjusting to the wind, the da ya entry into the water is equivalent to increasing the effective ship width. Therefore, fishermen say "the ship is stable only when the da ya entry into the water".

Fifth, judging from the shape of the bow and stern, the characteristics of the sand ship are square bow and square stern, and it can be equipped with a false stern or a protruding stern.

From a design perspective, a pointed bow can separate waves but is not good at suppressing them, while a wide bow can suppress waves but is not good at separating them. Which design to adopt depends on the actual situation of the ship. The bow and stern of the sand ship are not high, the depth is relatively small, the draft is shallow, and the bow and stern are square. This not only suppresses waves, but also enlarges the width of the ship, further increases the resistance to swaying, and can expand the cabin capacity and reduce the depth of the ship, making the main hull of the sand ship present the characteristics of "wide, large, flat, and shallow". The center of gravity of the whole ship is low, and the initial stability is particularly good. Even the "Military Records" of the Ming Dynasty commented on the sand ship as "the most stable among all ships."

The stern of a sand ship is more distinctive. From the rudder beam to the rear, there is a section called "virtual stern" or "false stern". If necessary, it can be extended further, called "extended stern" (it is said that sand ships with five masts or more usually have extended sterns). Adding virtual sterns and extended sterns at the stern is mainly to manipulate the sails near the stern and obtain more operating platforms. At the same time, it can also expand the space for personnel activities and storage at the stern, such as installing the winch for the elevator.

Sixth, from the perspective of the sail system, sand ships usually have multiple masts and sails, and use rectangular hard sails with closely spaced cross braces, which are a type of sail that can be used on both rivers and seas.

It is generally believed that the most notable feature of the sand boat is that it can sail against the wind, taking advantage of the side wind and headwind by adjusting the zigzag route. This is primarily due to the sand boat's multiple masts and sails. The sand boats of the Ming and Qing dynasties had 3 masts and 3 sails, 5 masts and 5 sails, etc. In the 20th century, there were large sand boats with 7 masts and 7 sails in the waters of Taihu Lake.

With the same wind-receiving area, multiple masts and multiple sails can reduce the center of wind pressure, lower the center of gravity, and avoid unfavorable factors such as difficulty in sailing and stability caused by high masts. When the sand ship enters the river from the sea, the wind force in the lower layer near the water surface is reduced due to the blocking effect of the wind force by the dams, trees, buildings, etc. on the shore. The use of rectangular, closely spaced cross-bracing hard sails with large aspect ratios (Note: aspect ratio means height, chord means width, and a large aspect ratio means a shape with large height and small width) is conducive to making full use of the upper wind force. In addition, these cross bars are regularly pierced and distributed on both sides of the sail, which makes it easier for the sail to receive wind from the front and back, improving the efficiency of the wind pushing the ship forward. Therefore, the sand ship uses a sail type that can be used for both rivers and seas.

Seventh, judging from the configuration of components and accessories, sand ships are generally equipped with large rudders, elevators, splashboards, water logs, and peace baskets.

Compared with other coastal ships, sand ships use relatively weak flat keels, but large and medium-sized sand ships generally have multiple sturdy keels on both sides of the ship. The keels are made by cutting a huge wood in half, which are strong and prominent. Large ships even use 5 to 6 keels, which run straight from the bow to the stern to increase the longitudinal strength. Numerous and sturdy keels, combined with the closely spaced transverse bulkhead structure, can still greatly improve the structural strength of the sand ship.

Sand boats are usually equipped with a rudder that can be raised and lowered because they wade in shallow water and sail on sand. After entering the sea, the rudder is lowered to the lowest point underwater, which can also reduce the sideways drift to a certain extent.

The design of the sand boat determines that it has good initial stability and turning ability, but its anti-drifting ability and heading stability are poor. It is very easy to deviate to the side or drift when sailing in sidewind or headwind. Therefore, special accessories such as water-shedding boards, water-stemming wood, and peace baskets are added to make up for these shortcomings.

The shedding board is also called "pry head" or "waist rudder". Depending on the size of the ship, the sand ship usually has 1 to 2 shedding boards on both sides of the middle of the hull. When in use, the shedding board on the leeward side is inserted into the water to prevent the sand ship from drifting sideways due to the wind. Shedding boards to prevent sideways drifting are not only equipped on ancient Chinese ships, but can also be seen on foreign sailing ships.

Sand ships sailing on the ocean are generally equipped with water-blocking logs. A "bottom map of a sand ship" is attached to the "Complete Case of Jiangsu Maritime Transport" in the Qing Dynasty. This sand ship diagram is marked with "water-blocking logs" and shows that they are installed on the bottom of the ship, specifically at the bilge, which is equivalent to the bilge keel on modern ships. Its function is to increase resistance and resist rolling to improve the stability of the ship.

Sand ships are also generally equipped with a safety basket, which is usually hung at the stern. When encountering wind and waves, the basket is filled with stones and thrown into the water. "Jiangsu Maritime Transport Case" records that "the safety basket is made of bamboo and filled with stones. When the ship is sailing on the ocean or there are wind and waves, the basket is placed in the water to prevent the boat from rocking." It can be seen that the safety basket is used to reduce the rolling of the sand ship in wind and waves, and is a rolling reduction tool.

References

1. Xi Longfei, History of Shipbuilding in Ancient China, Wuhan: Wuhan University Press, 2015.

2. He Guowei, Chinese Wooden Sailing Ships, Shanghai: Shanghai Jiaotong University Press, 2019.

3. Wu Chunming, Shipwrecks around the Chinese Sea: Ancient Sailing Ships, Ship Technology and Ship Cargo, Nanchang: Jiangxi University Press, 2007.

4. Lin Shimin, History of Shipbuilding in Ningbo, Hangzhou: Zhejiang University Press, 2012.

5. Zhou Shide, “A Brief Study on Chinese Sand Ships”, Journal of History of Science, No. 5, 1963.

6. Zhou Shide: "On the Traditional Ship Design in Ancient my country", in his book: "Diao Chong Ji: A History of Shipbuilding, Weapons, Machinery and Science and Technology", Beijing: Seismological Press, 1994.

7. Li Bangyan: "Sand Ship Type and Structure", included in the 1964 Marine Fishing Vessel Academic Conference Papers Collection Editorial Committee: "China Naval Architecture and Shipbuilding Engineering Society 1964 Marine Fishing Vessel Academic Conference Papers Collection Volume 1", 1965.

8. Xin Yuanou: Shanghai Sand Ship, Shanghai: Shanghai Bookstore Publishing House, 2004

9. Pan Junxiang, “Research on the Earliest Appearance of the Name “Sand Ship””, Metropolitan Relics, No. 1, 2015.

10. Ye Chong: "Interesting Names of Ancient Chinese Ships", China Water Transport News, September 13, 2020, p. 4.

11. Zhang Yili: "China's most representative traditional ship: sand ship", "Jiangsu Shipbuilding", 4th draft in 2021.

12. Yuan Xiaochun: On Ancient Chinese Shipbuilding Technology, in Shi Ping (ed.), Forum on Chinese Maritime Culture, Vol. 1, Beijing: Ocean Press, 2011.

13. Shanghai Shipbuilding Industry Bureau, Shipbuilding History Editorial Group, ed., Shipbuilding History, Shanghai: Shanghai Science and Technology Press, 1979.

14. Shen Yimin, “A Comprehensive Discussion on the Development and Evolution of Sand Ships”, Navigation, No. 3, 2015.

Source | Collection Restoration Department of China Maritime Museum

Pictures | Some pictures are from the Internet

Author | Ye Chong