In this continuation of a speculative study by the Fantasy Marketing Department of Maeda Construction Co., today’s technology is extrapolated into the year 2199 for a realistic look at the engineering prowess required to launch Yamato into space. As you’ll see, the rubber seriously hits the road in this part. Taking the concept to its dramatic conclusion admirably fosters appreciation for the disciplines of real-world construction work by viewing them through the lens of science fiction.
All content was created by Maeda Construction Co. Ltd. and the Yamato 2199 Production Committee.
Translation by Tim Eldred.
3: Center of Gravity Line Escape
See the original edition of this content here (posted October 28, 2012).
Hayashi and Yamauchi, the members of Maeda’s Civil Engineering Design Department who decided on construction methods to ensure Yamato‘s smooth launch, modified their draft proposal to the UN Space Command to excavate only up to the rear of Yamato‘s third bridge deck. They re-examined the UNSF’s Design and Construction Conditions, particularly (2) Take all possible measures for the launch of Yamato, in order to conform their design model to the details.
1} In order that Yamato can smoothly push away the ground covering the upper hull, grasp the properties of the rock and soil. Carry out replacement or improvement work if necessary.
Originally, IJN Battleship Yamato‘s hull was covered by a soft “uncompacted sediment layer,” so takeoff would be easy. However, it has already been mentioned that ground improvement would be required to excavate a large underground space. It was also because underground digging would not be detected by Gamilas above the surface. However, since the improved soil would strongly restrict Yamato‘s hull, there was the possibility that it would interfere with the launch.
The “multijet method” is a kind of high-pressure injection agitation system used for foundation improvement. It injects cement milk into the ground with ultra-high pressure to harden soil for land development, and it was agreed that this method would produce technical improvements for greater strength.
Compared to other high-pressure injection methods, the multijet method has several advantages. (1) In addition to a cylindrical shape, improvement is also possible in Free-form shapes. (2) Large-caliber improvement is possible up to 8 meters in diameter. (3) The machinery is comparatively small and requires only a temporary pilot tunnel. (The tunnel excavated in order to install the machinery in the improvement position, as seen in the upper part of figure 3.) Thus, it is possible to minimize the amount of excavated soil due to the small diameter.
It would begin with the digging of temporary horizontal pilot tunnels to the right and left of IJN Battleship Yamato‘s hull. The small multijet construction machine would be installed and perform ground improvement in the vertical direction (in cylindrical shapes, 8 meters in diameter), then move sideways and start the next one. After this, it was a matter of simple repetition.
The structure of the temporary pilot tunnel would be formed by the general approach of steel H beams and mortar spraying. Naturally, the small cross section of the multijet made for minimal excavation. The mechanics of the pilot tunnel and ground improvement would be carried out in parallel to shorten the construction period. (Figure 3)
2} Additionally, the activation of the main and auxiliary engines at startup will create a powerful driving force of propulsion. In order that it does not adversely affect the underground city, it is necessary to absorb the reaction force.
In order to stabilize the structure of the subterranean open space’s ceiling while minimizing the amount of excavation, a dome shape was considered with an arc falling away from the rear wave engine (Figure 4).
The side of the dome would catch the thrust of the Wave-Motion Engine and in this way aid the launch of Yamato. The only problem would be the engine’s effect on the underground city, since it was expected that intense pressure would hit the city through Tunnel 1 in particular. Therefore, two or more pressure bulkheads would be installed in Tunnels 1 and 2. They would also serve as defense partitions against Gamilas attack during Yamato‘s construction and also after launch.
3} Because the structure of the main engine provides direct backward thrust, a device must be included to assist in raising the bow.
The two men discovered an opportunity in smoothing out Yamato‘s launch by excavating to the rear of the third bridge.
They developed a proposal to perform ground improvement to the “uncompacted sedimentary layers” in front of Yamato so that if the ship moved forward in a straight line upon startup of the wave engine, they would act as a “ski jump stand.” However, a simpler answer was obtained when they focused on Yamato‘s center of gravity. Yamato‘s position was like that of a yajirobe [balancing toy], and it would be sufficient to simply raise the bow. They naturally arrived at excavating only for Yamato‘s stern half.
At that time, Maeda Construction Co. had not been told the position of Yamato‘s exact center of gravity. However, common sense dictated that if the excavation exposed Yamato‘s latter half and third bridge, Yamato‘s bow should rise first. Furthermore, the bow could be equipped with auxiliary thrusters, and if the nozzle of the wave engine was variable, then thrust vectoring would be possible.
When reviewing the third condition of the project (to ensure a smooth launch), the two thought that the risk of malfunction and damage posed by extra equipment would be considerable. Again, clearing a line in front of Yamato‘s center of gravity meant support equipment would have to be removed at the time of launch so Yamato‘s bow would rise and the ship could climb solely with its Wave-Motion Engine afterward.
In addition, the “floor” beneath the excavated dome was cut in a stairstep profile to reduce the amount of earth removal, a design which also provided ground support (underpinning) for the ship.
Incidentally, the building method of Yamato itself was entirely unknown. But the ship would be assembled block by block starting with the bow, and the system was to connect the blocks one by one, a support device for the launch was possible. For example, parts of Yamato would be assembled in the open space (where work was easier) and it was assumed that after they were completed, they would slide forward horizontally beneath the old Battleship Yamato camouflage for installation. Subsequent parts would be connected to the previous ones by a similar process.
In that case, the ground that would support the weight of these parts (in the area corresponding with Yamato‘s belly) would have to be fortified with earth anchors beforehand [footnote 8], and the next anchor would be installed in sequence as each of Yamato‘s parts were connected (figure 5).
The earth anchor’s settling power with the ground (friction) would prevent Yamato‘s bow from rising. If Yamato‘s overall weight and rigidity were supported by these earth anchors, it would be possible to omit rear supports from the design. (In the story, the lack of visible support mechanisms at Yamato‘s stern materialized from this.)
In any case, it was the conclusion of the two men that Yamato would use the earth anchor system. Therefore, a separation would have to be performed to cut Yamato‘s hull free of the anchors. (In the story, several small consecutive explosions occur at the time of launch along the sides of the hull, which resembles a primer cord detonation.)
Hayashi and Yamauchi of Maeda devised all of the above. It was the overall picture of “preparation for construction and launch.” However, it was still not enough. Although these two were professional “ground” men, they were not professional “tunnel” men. The presentation of costs for the work was still necessary to pursuade the UN Space Forces. Further detailed study with the help of a “tunnel” pro was the key to the future.
The journey of Maeda Construction’s technical experts would continue for a while yet, until the day they passed the baton to the journey of Space Battleship Yamato.
Footnote 8: Earth Anchor
A long steel rod is inserted into the ground to provide a connection between the “fixed part” and the “structure” to be developed. For example, to stabilize a slope and prevent its collapse. In this case, the anchor (fixed part) is struck directly under Yamato (the structure) to prevent a lifting effect.
4: Imitation of Expression
See the original edition of this content here (posted November 4, 2012).
Upon further study, Hayashi and Yamauchi required a new force: Mr. Kagawa of the Tunnel Group Civil Engineering Department.
Kagawa, who was entrusted with the on-site accounting, calculated the uniformity coefficient of the soil at 1.5 to 2.9% (~5%) and the uncompacted layer at 0.2 to 6.9% (~10%). [A measurement to account for the variable size of individual grains.] Put simply, “the soil would collapse smoothly when digging, like a giant sandbox.”
After reviewing the draft proposal, Kagawa stated that “considering the shape of the subterranean space, it is also necessary to carry out foundation improvement at the rear of Yamato. We would like to review the entire shape.” Murmurs could be heard as the memo was silently written on a whiteboard. These memos were compiled into draft figure 6.
At first, the biggest change was the position of Shaft 1 (to be used for the removal of shear.) The shaft directly under Yamato‘s rear engine nozzle in figures 1 and 2 was moved to a position that was incorporated into the underground space at the time of completion.
The shaft was intended as a “shear disposal hole” at the time of excavation, but it was moved to equalize the transportation distance from every point within the large space. Minimizing the total distance was a good way to increase the efficiency of the digging operations. The shaft position was arrived at through trial and error.
Additionally, Tunnel 1 would serve as an advance pilot tunnel (for both Tunnel 2 and the open space), and because it was dug at the boundary of the sedimentation layer, it was decided to adopt the TBM [Tunnel Boring Machine] construction method which made it easier to respond to ground changes. This tunnel would be dug prior to the main excavation, so the soil properties could be better understood when they presented difficulties.
A TBM is literally a machine that digs tunnels, which often has a cylindrical cross-section and is about the same size as the tunnel to be dug. The use of this machine makes it possible to (A) not overexpose the tunnel walls and (B) enable stable construction regardless of changes in groundwater, soil, or sand. There are various definitions and types of TBM, and a shielded type was chosen to avoid exposing soil and sand in the interior of Tunnel 1. In this way, the main body of the tunnel would formed by segmented pieces produced in a factory. These segments would be assembled by the shield machine to enable stable and effective construction.
At first, Tunnel 1 was supposed to go only in the direction of Yamato‘s stern, but to further shorten construction time, it was decided to diverge into a branch at the middle to the starting position of Shaft 1. Thereafter, the former Tunnel 1 was referred to as Tunnel 1-1 and the latter was named Tunnel 1-2. Ordinarily, a diverging branch in the middle of a tunnel was not desired, since the dynamic stability of that tunnel would be lost. Since there were still a few construction examples of H&V (Horizontal and Vertical variation) in the 22nd century, the shield method of construction was adopted.
H&V is done with two cylinder-shaped excavators connected in parallel that resemble a figure 8 when seen from the front. They are connected by an articulated device that allows them to move independently. While the cylinders are connected, they can rotate like fan blades along the directional axis of the tunnel, moving forward as they excavate. Using this in subway construction, for example, two side-by-side tracks can be dug horizontally, or the cylinders can be rotated into a stacked vertical configuration under a narrow roadway (dictated by land ownership restrictions). It is even possible to separate the machines onto different pathways, though once detached, it is not possible to rejoin them (see figure 7).
The finished size of Tunnel 1-1 was 12.6 meters in diameter, matching the specs of the Tokyo Bay Aqua-line, which was dug with the best possible shield performance despite its primitive construction. This large cross-section ensured a constant access route with twin paths to remove shear and import new materials. It is very effective in the construction industry to properly extrapolate the achievements of existing designs and planning.
The diameter of Tunnel 1-2 and Shaft 1 (after the completion of Tunnel 2) was set to a 3-meter cross-section in which passages could be dug using a raise-boring method. In order to maximize the cross-section of Tunnel 2 for such requirements as loading planes onto Yamato, the NATM [New Austrian Tunneling Method] was adopted. This is considered the standard for construction of mountain tunnels, the greatest example of which was the 140 square meter tunnel section of Japan’s ancient 2nd Tomei expressway.
During the excavation of the large open space in the second stage of digging, a continuous conveyor belt was used in Tunnel 1-1. Shaft 1 was also dug during the second stage, and during the third stage shear was dropped down the shaft to a conveyor belt leading out through Tunnel 2. The excavation was divided into these three general steps in order to prevent collapse of the large underground space.
In addition to material supply during the excavation, Tunnel 1-1 was also used for ventilation. To calculate the necessary amount of air during tunnel construction, a wind pipe is installed near the face. By pumping in fresh air, stale air is gradually replaced (circulated) at the required flow rate. During the second stage of digging, it was possible to perform ventilation on Tunnel 1-2.
After study of the main tunnels was finished, there was no rest for Kagawa and Hayashi, since the key to building the domed open space was to examine the “uncompacted sedimentary layer” at Yamato‘s flanks for ground improvement. The quantity of machinery used in the multijet method to dig the pilot tunnel was considered from the cross-sectional plan shown at right (figure 8).
To prevent the roof of the open space from collapsing during excavation in the “uncompacted sedimentary layers,” digging would begin after improvement was carried out in multiple pipe form. Several pilot tunnels would be dug into the improvement range as follows (figure 9).
Since shortening the time needed for completion was top priority, 10 sets of multijet machines would operate simultaneously for rapid execution in 24 hours. In the plan view in figure 9, Yamato is shown as a rectangle with multiple circles extending out to its left and right to represent the improvement range. Each measures 8 meters, the diameter of a single multijet. The shape of the improvement area is cylindrical to a depth of 24 meters. The cost came to approximately 30 billion yen.
To keep the explanation brief, Kagawa and Hayashi consolidated their construction steps into figures 10, 11, and 12, titled “Construction preparations and launch preparations for Space Battleship Yamato.”
[See a translation of this diagram here.]
A notable point in figure 10 is the position of Tunnel 1-1 as described earlier, which was changed as a result of further study. It was moved from beneath Yamato as shown in a previous draft (figure 6) and transferred “outside” the construction range of the large open space. In the draft proposal (figure 6), the portion of Tunnel 1-1 closest to Yamato disappears after the open space is excavated. Although a bridge (trestle) is needed between Tunnel 1-1 and Yamato, it would come at a high cost in time and money. In the final draft, on the other hand, there is no change to Tunnel 1-1 even after the open space is excavated, and it becomes a possible supply route to Yamato (figure 15). Also, the completion of ground improvement is noted in figure 10.
Next, the construction of the open space is shown (figure 11).
[See a translation of this diagram here.]
Construction of the vertical shaft (Shaft 1 in the diagram) begins at the same time construction is completed on Tunnel 2, and it is completed at the same time as the second stage of the large open space. After this, the loading of equipment for the building of Yamato (= Yamato construction) can commence (Step 6). Excavation continues in the open space and it is soon connected with Tunnel 2 (figure 12). All vehicle movement is shifted to Tunnel 2 at this point.
The role of tunnels 1-1 and 1-2 is now finished, and concrete blockades are installed as a countermeasure to the propulsion force of Yamato‘s Wave-Motion Engine upon startup.
[See a translation of this diagram here.]
In the beginning, the plan was to install pressure bulkheads in Tunnels 1-1 and 1-2 to protect the underground city from Yamato‘s propulsion force and bomb blasts from above, but it was decided that concrete blockades were both reliable and cheaper. Traffic and vehicles carrying equipment to Yamato would be aggregated to Tunnel 2 to reduce costs. Naturally, the bulkheads in Tunnel 2 were structured to allow for vehicle traffic.
Finally, the time for Yamato‘s launch arrives (figure 13) and Maeda Construction’s job continues, highly interlocked to the movement of the ship even during the launch process.
[See a translation of this diagram here.]
Construction for the launch process takes into account the scale and details of “anchor” and “shoring” (ground support).
The tentative weight of Yamato, its temporary camouflage, ancillary craft, margins of ammunition, etc., was estimated at below 100,000 tons (figure 14).
With all studies concluded, calculation of the construction costs and timeframe would soon be finished. Kagawa gave a heavy sigh. Despite all efforts, a period of one year or more was required before construction of Yamato could start.
“If the demands increase, we will devise farther,” Hayashi said.
The team members instantly prepared themselves for the worst since they would present their proposal to a UN Space Forces official the next day.
Shown at right: Kagawa (left) and Hayashi (right) of Maeda Construction review preliminary arrangements with a UN Space Forces official (center).
The voice of the UN Space Forces official resounded in the drab conference room.
“The construction of Yamato would start 410 days later.”
“Yes. I believe this is the best balance of cost and safety.”
“Construction completion would be limited to 470 days at a cost of 120,738,160,000 yen.”
The female official, who gave off a slightly cold impression, asked if any of the specifications and necessary time could be squeezed off the top.
“Because an underground city is near this area, the length of Tunnel 1-1 is a little less than 900 meters. This is the amount needed.”
The long meeting ended and the official decided on a final presentation to the upper echelon of the UN Space Forces the next day. There was no time to spare.
“Where is this battleship going? Will it search for a planet for emigration?”
Hayashi asked the question, but as expected she did not respond. The words were spoken to find some hope, which seemed to be the greatest possible service to the staff of Maeda Construction Co.
While finishing the final draft diagram, Hayashi thought about the crew of Yamato. When Tunnels 1 and 2 and the vertical shaft were blockaded with earth and sand to take all possible measures against damage to the underground city. The crew would be isolated with no going back. What would they be feeling at that moment?
“If the launch fails, can we go back underground?”
No, the tunnel and shaft would be blockaded, and they may conversely feel trapped and suffocated. A feeling of despair that they had been abandoned…
“Therefore,” Hayashi thought, “after we’ve left, our work becomes even more important at the time of Yamato‘s launch.”
There were 411 days left until the start of Yamato‘s construction.
The End[Addendum: since the value of a monetary unit in 2199 is unknown, Maeda’s Fantasy Department calculated cost based on the 2012 value of the Japanese yen. As of February 28, 2013, the US dollar equivalent to the total cost estimate was about $1.2 billion.]