Fourth Bridge
Fourth Bridge | |
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Type | Airship |
Creators | Alethi |
Captain | Navani Kholin |
World of Origin | Roshar |
Universe | cosmere |
“She is an odd ship, to be sure, but majestic in her own way. ”
The Fourth Bridge is Roshar's first airship. It was built in the Shattered Plains, and named after Bridge Four.[1]
Design
“Hundreds of laborers in Urithiru turning winches to raise and lower the ship. Dozens of chulls used to move it laterally. Thousands of fabrials to facilitate both—all needing to be perpetually reinfused. Careful synchronization via a half dozen spanreeds to coordinate maneuvers. ”
The Fourth Bridge is a rectangular, wooden box; a hundred feet long, sixty feet wide, and about forty feet high, with three decks within. Fans are built into the back to increase speed, though for now, the speed difference they provide is minimal.[1]
The back half of the upper deck is covered by a semi-round roof, while the front half is open to the air, and surrounded by a railing. Bridge Four's original bridge is embedded into the floor; the Windrunners have a habit of kneeling down and touching it before taking off. A command station, composed of several tables, is typiacally placed in the sheltered part, though in some cases, it might be moved to the front. The furniture is bolted down.[1][3]
The lower decks serve as the hold. It has wide door that open, allowing large amounts of people to come in and out. It functions akin to a drawbridge; normally, it is part of the wall, and can be lowered and raised by ropes to open and close it. While sparsely-furnished, the holds can accomodate several hundred people.[1] There are numbers painted on the walls, dividing the hold into a number of sections.[2][3]
Mechanics
The airship doesn't so much fly as it floats. There are hundreds of gemstones forming a lattice of masive Cojoiner fabrials embedded into the ship. They are connected to a pair of "dummy ships". One of the dummies is hanging off the side of the Urithiru plateau; the other is built on the Shattered Plains.[4][5] The airship is steered from those two lattices; the Fourth Bridge communicates its needs to them through spanreeds. As they cannot be used for long periods of time due to movement, the scribes use them by turning them on and off, creating a code of blinks.[1]
The cojoiner fabrials are isolated using aluminum so that only certain planes of movement are transferred between the paired gem halves. The Urithiru structure can only convey vertical motion; the Shattered Plains lattice can only transfer horizontal motion.[5][1] To allow the ship to continue moving when the space for the lattices runs out, an additional aluminum mechanism is used to reverse the motion while the gemstones are temporarily unhooked.[1]
The entire structure requires significant manpower to function properly. In Urithiru, hundreds of people operate the winches that raise and lower the vertical lattice; on the Plains, squads of chulls are used to move the ship horizontally. The entire structure requires hundreds of gemstones to be perpetually infused with Stormlight.[1] Fans have been installed to ease the load on the horizontal fabrials, but as of right now, they are barely functioning. There are also weight concerns, as adding too much mass to the existing structure might cause the gemstones to crack.[2]
History
Development
Floating Platforms
Navani Kholin began conducting her first tests a few months after arriving at the Shattered Plains, in the last year of the War of Reckoning. The first conducted experiment was comprised of a tall tower, with its top and the column a separate pieces, and a paired circular platform with crenellations. After infusing the embedded fabrials with Stormlight, when the pillar was rolled away, the top of the tower remained floating. As the top was pulled down, the platform rose into the air, creating an archer parapet unassailable to anyone standing below. It seems that even back then, there were plans to do more with the technology.[6]
Over time, Navani and her ardents improved the platforms even as they began planning for more ambitious projects. Shortly after the True Desolation began, Navani began planning for proper airships; her initial designs were more ship-like, with massive sails attached to the bottom of the hull.[7] However, proper construction began only after the Battle of Thaylen Field, as Navani threw herself into work following the death of her son, Elhokar.[1] A few months after the battle, the Alethi built a pair of massive platforms off the sides of the Urithiru plateau as their early experiments. By then, rumours of what they were planning began to spread covertly among the high-ranking members of the coalition.[8]
Aluminum
As the twin platforms were being constructed, the ship Wandersail set out to explore Aimia. As a favor to the expedition's leader, Rysn Ftori, Navani sent along Rushu, an ardent specializing in new fabrial designs.[8] Rushu attempted to make Rysn's chair float; however, the fact that the cojoiner fabrials had to repeat the exact motion -- or the reverse of the exact motion -- of each other meant that the applications were severely limited.[9]
A breakthrough came from Huio, one of the Herdazian Windrunners assigned to assist the expedition. To sate his curiosity, Huio disassembled one of Rushu's spanreeds and began experimenting on the gemstone with aluminum. After he put the spanreed back together, it began to behave oddly, transferring the movement of its cojoined twin in an odd, jittery way. Realizing this would be a problem that couldn't be hidden, Huio and the other Windrunner on board, Lopen, brought the broken spanreed to Rushu.[10] Upon examining it and experimenting further on Rysn's chair, Rushu realized that Huio managed to use aluminum to isolate the spanreed's planes of motion, so that only movement in specific directions was transferred between the two. This allowed for a creation of a floating chair that could move freely by being pushed around.[11]
Rushu later sent the information about Huio's discovery to Navani, who ordered further experiments. As a result, eventually, Falilar, one of her ardents, made a breakthrough that allowed for an airship to be constructed.[5] A new design, based off the chasm-spanning bridges from the War of Reckoning, was built and tested on the Shattered Plains. After months of deliberation, it was named the Fourth Bridge, after the people who, over a year prior, had saved House Kholin from destruction.[1]
Hearthstone Mission
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