New Submarine Production Hall at Huludao: To be, or not to be.

There has been a plethora of Chinese-language blog posts and articles since mid-August 2016 concerning the new assembly hall at the Bohai Shipbuilding Heavy Industry Company’s (BSHIC) shipyard in Huludao. The English-language posts and articles that followed faithfully repeated the Chinese content, which claimed that the assembly hall is where the next generation of Chinese nuclear submarines would be built. Some Chinese and English articles even went so far as to say that production would proceed at a rapid pace given that the hall could build up to four submarines simultaneously. Subsequent blog posts speculated that a total of six submarines could be built at the same time because there are three production bays in the hall.

A constant hazard in relying on foreign open-source information is that a researcher could mistake circular reporting for independent confirmation of a claim. In this case, the majority of Chinese Internet posts and articles can be traced back to an August 18, 2016, blog post titled Construction of New Ship Assembly Line at Bohai Shipyard, Or Will Build New Nuclear Submarine (渤船新型总装生产线建设, 或将造新核潜艇), which highlighted BSHIC chairman Li Tianbao’s visit to the facility. Interestingly enough, the only place in the post where the characters 核 (nuclear) and 潜艇 (submarine) appear is at the end of the title. They are not used in the text at all—nor, as will be discussed later, anywhere in the most authoritative source available: the shipyard’s original August 17 announcement titled Chairman of the Board Li Tianbao Conducts an On-Site Inspection of the New Assembly Line Construction Project (李天宝董事长到新型总装生产线建设项目现场调研). Some of the derivative articles readily admit the nuclear submarine construction claim was speculative, but given that Huludao is the only shipyard that builds nuclear submarines in China, that seemed to be a reasonable assumption to many Chinese bloggers. Within several months, however, that speculative assumption had largely morphed into a definitive conclusion—with no evidence or analytical steps to support the transformation.

This article will examine the Google Earth imagery history of the new production facility at the BSHIC Huludao Shipyard through the lens of accepted civil-engineering standards and construction practices—including those used in China. For multiple reasons that will be shown, it is extremely difficult to support the claim that Huludao’s new facility will build the next generation of Chinese nuclear submarines.

Not the First Step

The rapid construction of the new BSHIC assembly hall that China so proudly lauded in August 2016 is not as exceptional as many of the blog posts would have the reader believe. This most recent expansion of the shipyard’s territory is only the latest in a series of equally impressive land reclamation and facility construction phases that were executed in very short order. The first expansion began soon after the Medium and Long Term Development Plan for Shipbuilding Industry 2006–15 was adopted in August 2006. The main emphasis of this ambitious national plan was to develop and expand China’s shipbuilding core concentrated in the Bohai Bay area, the Yangtze River Delta and the Pearl River Delta into world-class shipyards capable of producing large, high-tech, high value-added merchant ships.

During the first phase of the expansion project, land reclamation efforts at Huludao focused on the southern shore of the peninsula along the shipyard’s northern perimeter. This initial expansion paved the way for the construction of the first three hundred thousand deadweight-ton (DWT) dry dock as well as China’s largest multi-bay production hall. So incredibly quick was the construction of these new facilities that the keel for the shipyard’s first very large crude carrier (VLCC) tanker was laid down in July 2007—before the dry dock was even completed.

By early 2008, the first three hundred thousand DWT dry dock was finished and the second phase of land reclamation was well under way along the southeastern end of the peninsula, together with a massive effort along the peninsula’s northern coastline. The southeastern expansion provided new land for the construction of the second three hundred thousand DWT dry dock, as well as preparing the east end of the peninsula for phase three work. The northern expansion was considerably larger than any of the other reclamation efforts, adding nearly five square kilometers of new land. By the spring of 2010, the southeastern segment was largely completed and the second large dry dock nearly finished. As with the first dry dock, a VLCC tanker was seen under construction in the second dock before the dock was finished. The second dry dock was likely completed late in 2010.

The third phase of land reclamation began in early 2013 on the northeastern edge of the peninsula. The eastern end, where the new production hall would eventually be built, started reclamation efforts by the spring of 2014. In late January 2015, the newly dredged sandy soil is almost entirely in place and construction equipment and materials can be seen on the new ground in satellite imagery.

The Foundation Is Everything

The foundation for the new assembly hall was first noted as being under construction in the satellite imagery of June 6, 2015. Numerous pile drivers were seen to the north of the construction site and the slab areas, and deep footings showed the presence of a considerable number of piles. Large piles were noted as early as January 2015 when test runs were likely conducted on the new soil. Analysis of the piles indicates they are about fifteen meters in length, and have a side length or width on the order of 0.5–0.6 meters. The appearance of the piles strongly suggests that they are made of concrete. These dimensions are consistent with Chinese-manufactured reinforced concrete, solid square piles that have an estimated compressive strength between thirty and forty megapascals (4,350 to 6,000 pounds per square inch) based on Chinese product information and published national standards. This very roughly equates to an axial loading bearing capacity of about 100–150 metric tons.

Given the short length of the piles, they are undoubtedly friction piles that provide support to the foundation slab and deep footings through friction forces with the soil—the piles themselves don’t rest on bedrock. As sand is a coarse grain, noncohesive soil, the use of friction piles is an accepted method of building a deep foundation. This type of pile is noted on Chinese product websites as having a long life, good corrosion resistance and good performance in water. It is also well suited for use in industrial plants, embankment walls, bridges, port facilities and other coastal-building projects.

Visual inspection of the slab foundation shows that there are eight piles in each row, with the spacing between the piles measuring about 4.5 meters. The spacing between most of the rows is about the same, with some rows being closer. This spacing is consistent with the piles functioning as compaction piles that compress and densify the soil, thereby stabilizing it. By keeping the piles at a distance of six to eight times the pile’s width, the areas of highly compacted soil generated by each pile do not overlap. This increases the load-bearing capacity of the weak sandy soil and reduces uneven settling. However, as the piles are spaced far apart, they do not interact with each other and thus act independently. This means the foundation is not particularly strong and will not be capable of supporting very heavy loads.

By comparison, the deep footings for the larger structural supports also have eight piles, but they are much closer to each other, measuring about 2.5 meters apart. The distance between the deep-footing piles is close to the minimum spacing requirement, 3.5–4.0 times the pile’s width, as specified in China’s national standards for building pile foundations, and is consistent with U.S. building practices. These piles are grouped together so that they can be covered by one thick concrete pile cap that will distribute the load evenly. This indicates that the piles will be working together and are capable of supporting very heavy loads.

By July 2015, the three production bays had most of their concrete slab sections poured. Each foundation slab is about 276 meters long and thirty-three meters wide. The slab appears to be poured in two layers; a third, thin finishing layer would be added after the exterior was completed. The varying colors indicate that the concrete sections are at different stages of curing. The total thickness of the slab is difficult to estimate, but appears to be much less than one meter. The lack of any significant excavation (fill material was brought in) and the presence of little to no shadow indicate that the slab is near ground level. This, too, suggests the foundation will not be capable of supporting very heavy loads—a completed nuclear submarine would weigh in excess of four thousand tons.

Examining an analogous U.S. shipbuilding facility built largely with concrete components, the Bath Iron Works Land Level Transfer Facility in Bath, Maine, provides an appreciation for the necessary construction to support the weight of a naval vessel. This facility assembles Arleigh Burke-class guided missile destroyers with a light displacement on the order of 6,800 tons. The deck slab is supported by 0.71-meter diameter octagon-shaped, prestressed, reinforced concrete piles that are spaced at 1.8-meter intervals for the areas with the heaviest loads. This is the minimum spacing requirement for end bearing piles (2.5 times the pile’s diameter) that rest on bedrock. The deck slab itself is 0.51 meters thick and rests on 0.6-meter thick support beams.

The Chinese could have built a foundation as capable with friction piles, but this would have required piles that were longer, stronger and spaced about as close as those in the deep support footings. The piles would also need to be grouped together for mutual support and covered with a thick pile cap and finally, a thicker slab. The new Chinese assembly hall’s foundation is not in the same league as the one in Bath, Maine.

Based on the analysis of the new building’s foundation, it can be concluded that it was most likely designed to support objects that weight on the order of several hundreds of tons, not several thousands of tons. This raises serious doubts as to the claimed function of the new assembly hall’s production bays. Also, it is not the only major obstacle on the path to nuclear submarine production.

Lack of a Continuous Path

By May 2016, the exterior of the new assembly hall was proceeding at a brisk pace and the production bay gantry cranes were visible through the open roof areas on the hall’s east end. The satellite imagery also showed pile drivers placing the same fifteen-meter-long concrete piles into the soil outside the west end of the building, and along a path leading toward to the second three hundred thousand DWT dry dock.

The driven piles in front of the new hall covered a sizeable area, over thirty thousand square meters, indicating the shipyard was building a large transverser to facilitate moving completed objects from the assembly hall to a railway system. The spacing of the piles in the transverser area and along the rail lines is consistent with the foundation of the assembly hall, indicating they have a similar load-bearing capacity. By June 2016, slab sections for the transverser and the railway tracks had begun being poured. Imagery from December 2016 showed considerable progress on both the transverser and the railway lines. This photograph also provided a clearer understanding of the arrangement of the rails and the railway’s length. From the end of the transverser to the dry dock, the railway is an impressive five hundred meters long with four rails. The spacing between the inner two rails matched the rail gauge (≈six meters) from the production bays. The outer rails are probably for prime movers/tractors that will push structural cradles on wheeled bogies carrying completed objects to the dry dock.

Even if the railway could support the weight of a completed submarine, there are several “roadblocks” at the western terminus that prevent the transfer of any large vessel into the dry dock. Google Earth imagery shows the rail lines end at a massive dry dock wall. This wall is about six meters wide and at least one meter tall—there is no way to move a large, very heavy vessel over this wall. Furthermore, there are no rail lines in the shallow slipway. This indicates that there is no way to directly transfer objects to the slipway by rail. Rather, objects will have to be lifted off the structural cradles and placed in the slipway or dry dock by the gantry crane. The crane’s rails extend past the dry dock wall, enabling the crane to position itself directly over the railway. A significant limiting factor, however, is the gantry crane’s weight limit of six hundred tons—sufficient to lift hull sections, but an order of magnitude less than the weight of a completed nuclear submarine.

 

The last obstacle is the shallow depth of the slipway. According to BSHIC’s Production Capacity webpage, the three hundred thousand DWT dry docks have a depth of 12.75 meters. Comparing the two in satellite imagery shows the slipway has a depth of 3.5 to 4 meters—far too shallow to float a submarine off of its support cradles. The slipway would have to be completely rebuilt to be able to transfer a submarine from the railway to the dry dock. And while such an option is feasible, recall that the planned expansion in the Huludao Shipyard’s production capability was proposed and approved nearly a decade earlier. If the Chinese had intended for the assembly hall to produce the next generation of nuclear submarines, then a lifting dry dock similar to the fifty thousand DWT dock on the other side of the bay would have been installed. Without a dedicated path to transfer a large completed vessel from the rail line to the dry dock, the only way in is by the gantry crane, and then only up to the crane’s lifting capacity of six hundred tons. This means only sections of a large ship’s hull (grand blocks) can be moved into the dry dock. A more detailed examination of these issues can be found at http://www.admiraltytrilogy.com/wardroom.html

Original Announcement?

Given the clear limitations of this facility, why has there been so many articles reporting that it is intended to produce nuclear submarines? The answer can be found by looking at how the information contained in BSHIC’s original announcement was altered and then spread by individuals with varying degrees of personal bias. As noted earlier, many of the Chinese blog posts and populist magazine articles can be traced to the August 18 post on tieba.baidu.com, where the terms “nuclear” and “submarine” are only present at the end of the blog’s title; there is no reference at all to these terms in the body of the post. That is because the August 18 post is not the original announcement of the BSHIC chairman’s visit to the new assembly hall.

On August 17, Huludao Radio & Television published an announcement from the Center for New Media Communications Bohai Shipbuilding on mp.weixin.qq.com, a website that is virtually identical to the August 18 post. Four out of five photographs in the August 18 post are also in the August 17 announcement and the main text is identical. The only textual difference is that the August 17 announcement makes no mention of nuclear submarines in the title. What this suggests is that the author of the August 18 post reposted the same article with an additional photograph and modified the title, adding “or will build new nuclear submarine(s)” (或将造新核潜艇) at the end. This modification was the snowball that began an avalanche of misinformation that has permeated Chinese and English language reporting on this new assembly hall.

A popular graphic technique used to promote the idea of new submarine construction at Huludao is the merging of a photograph from the August 18 post with a shot of a Western or Russian submarine construction hall. Invariably, the blogger stresses the point that the two photos look very similar. In fact, an assembly hall’s interior will look similar regardless of what is built in it. A more apt comparison would be to juxtapose the same photograph of one of the new assembly hall’s production bays with an image taken from BSHIC’s production-capacity website, which shows one of the production bays in the 2008 assembly hall. One can just as easily make the argument that the two photos look very similar. The only major difference between the two BSHIC assembly halls is the presence of a rail system in the new one, which is required because of the unusually long distance from the assembly hall to the dry dock.

Conclusion

From a comprehensive review of Google Earth imagery and Chinese language sources, it is extremely difficult to support the claim that Huludao’s new facility will build the next generation of Chinese nuclear submarines. Analysis of the foundation of the new assembly hall indicates that it is insufficient to support the load of a completed nuclear submarine that weighs in excess of four thousand tons. Even if it could, the lack of direct access precludes a completed submarine from being transferred to the dry dock. This means that only grand blocks—prefabricated sections of a ship—can be physically moved into the dry dock; and only up to the six hundred ton weight limit of the gantry crane.

Together, these conclusions point toward the most likely explanation for Huludao Shipyard’s latest production facility: high value commercial ship construction. If China’s Medium and Long Term Development Plan for Shipbuilding Industry 2006–15 is the driving force behind the entire expansion effort at the Huludao Shipyard, then the goal of this plan is the more likely reason for this new assembly hall. And that goal is to be able to produce large, high-tech, high-value-added merchant ships, such as Very Large Crude Carriers, high-capacity twenty-foot equivalent unit container ships, and liquefied natural gas and liquefied petroleum gas tankers—not nuclear-powered submarines.

Christopher Carlson is a retired naval officer and scientific and technical intelligence analyst specializing in naval warfare issues. He retired from the Defense Intelligence Agency in 2010 as a senior intelligence officer overseeing the production of technical intelligence products and presentations to national decisionmakers and the acquisition community. He is also an award winning war-game designer who has numerous products in the Admiralty Trilogy series. Additionally, he has coauthored eight military thriller novels with New York Times bestselling author, Larry Bond.