Last week we talked about our previous seastead designs, and how we arrived at Design 4, a very resource efficient and economical design. Today I will explain why we scrapped Design 4 in favor of slightly more expensive spar based designs. The reason has to do with stability. When we began running our wave simulations we took two motion types into account: Heave and Pitch. Imagine an empty bottle floating on the surface of the water. When a wave comes by, the heave is how high it rises up into the air on the wave, and how fast, and the pitch is the back and forth rocking of the structure. When we ran our first storm wave simulation, Design 4 rocked back and forth in the waves by about 12.5 degrees in either direction, but between the crest and trough of the waves, it bobbed up and down in the water at speeds as fast as 3.17 meters per second. Keep in mind that the force of earth’s gravity is about 9.8 m/s meaning that when rising up on a storm wave a person inside the structure would feel about 130% of Earth’s normal gravity. This is enough to make some people buckle under their own weight while standing, not to mention the force acting on them at an angle of up to 12.5 degrees. In this kind of environment, dishes would be thrown out of cabinets and be smashed on the floor, tables and chairs would slide across the room, and furniture would be overturned and broken. We had to come up with a solution.
In most of our early wave simulations, Design 4 proved to be too unstable in large waves. People and furniture inside of this structure would have been shaken around too roughly.
Design 4 would have been built to allow seasteads to connect to each in rows, with some having 4 connection points to create intersections.
While working on Design 4 we refined our formula for Seasteading Cement. The roadways would have been made of a cheaper and more elastic material so they could be easily replaced.
The first thing we did was join multiple structures together to allow them to stabilize each other. This worked to a limited degree. We reduced our angle of pitch from 12.5 degrees to only 9 degrees and our heave from 3.17 m/s to only 2.92 m/s, but this still wasn’t good enough. In order to make this platform truly stable in storm waves, we would need to drastically change the design.
The heave plate underneath our structure is designed to increase friction when the seastead is being pulled up into the air by a large storm wave, so maybe by adding a second heave plate below the first we would be able to cut these numbers in half. When we ran a simulation on a double heave plate design we found the the pitch was now 8.5 degrees and the heave had been lowered to 3.06 m/s, a marginal change at best. Improvements still need to be made.
5 double heave plated seasteads have been joined together to further increase stability, while improvements were made it was still too unstable to live in during storms.
Then we ran a simulation on a design lifted out of the water on a huge deep sea spar. The results were striking. The amount of wobble placed on this new seastead was reduced to only 3.7 degrees, and the heave had been lessened to only 0.962 m/s. We decided to abandon Design 4 and make the spar based design our new Design 5.
From here we got creative. The team sat down and asked ourselves ‘What can we do with spars? Can we have multiple to carry more weight? What happens if we make them thinner? Or thicker? Is there a perfect spar design? How do we make them cost effective?’
We ran several more simulations from here, to experiment with spar based builds. First we tried to add 4 spars underneath our house instead of just one, this reduced our pitch to only 1.79 degrees but increased our heave to 1.03 m/s. By adding more spars we were increasing the surface area in contact with the water. The increased surface area allowed more water to be displaced when a wave rolled through, which in turn had a greater effect on the up and down motion of the vessel, although by spreading out the spars we spread out our weight which gave us greater stability against rocking. It was a trade off.
Next we tried to balance the whole structure on a single spar once again, but make the spar massive, a full 50 meters deep into the water. This kind of structure could only be assembled in the deep sea, as most places near shore would be too shallow for this kind of seastead to exist. By having most of the spar deep underwater, the amount of added water displaced or removed by passing waves was proportionately smaller. This meant that large storm waves would have less of an effect on the structure as a whole. For our deep sea 50 meter spar, the pitch was reduced to only 2.0 degrees and the heave to 0.14 m/s.
Lastly, we tried to go wider and have a large house on top with 9 spars below to see if we could reduce pitch to the minimum possible. We found that when adding multiple spars we could allow the upper portion of the structure to support more weight. This meant heavier materials, a more durable home and more stories to the structure being built, perhaps up to three or four floor buildings. This 9 spar design had only 1.42 degrees of pitch with 2.78 m/s of heave. This means that while pitch was somewhat below average and the structure could support heavier buildings, the heave had been increased significantly.
Finally we decided to reduce the size of the house down to only 1000 square feet, and settle on a 4 spar design that had shown itself to be one the most cost effective for production. We called this design the HEX1000 because of its hexagonal shape.
The HEX1000 offered the most flexibility of any design, it had two floors, and walls could be removed from one side to join two Hexagons together, creating a single connected structure, now a 2000 square foot house. In theory an infinite number of HEX1000s could be connected together to make as large of a building as you could want, provided it was limited to two stories.
Cities could be constructed like legos with each hexagon being a different building and housing a family or being connected to neighboring hexagons to form a shopping mall. By breaking down the city into it’s smallest component, a hexagon, we can offer the most flexibility possible in creating floating communities at sea….. or can we?
The thought occurred that if a house is the smallest unit of a floating city, what is the smallest unit of the house? With the current design, house construction was chunky. You could choose between a single hexagon, with 1000 square feet of interior space, or two hexagons for 2000 square feet, or 3 for 3000 square feet. But what if I wanted only 1 floor? Or 3 floors? Or 1500 square feet? Or a lawn with grass? It occurred to us that the smallest unit of the house was actually the spar. A single spar could hold up a certain area of house above it, the smaller the spar, the less surface area it could hold. So what if we created small spars that could attach together to form one larger platform, and build each house atop this platform to the specifications of the home owner? This would maximize flexibility in home design.
When we made this piece of concept art we were beginning to think about having the house and platform become separate structures.
But it also solved another problem; transportation. Around this time Mitchell Suchner was in the Philippines scouting out the ideal construction location for our prototype. Much of the coastal area around the world is already occupied either by bustling ports or as residential areas, and the Philippines was only marginally better. We found that while there were plenty of industrial zones inland that we could build from, industrial zones on the coast were hard to come by. This meant it may be necessary to build inland and then move the pieces of the seastead to the water later for assembly. Arktide seasteads will be constructed from our specialized Seasteading Cement, which is lighter weight than normal cement, but the ballast necessary was still massive. A ballast for Design 5 was a solid block of Seasteading Cement which weighed in at a whopping 79 metric tonnes. The ability to transport this from a construction site inland to the ocean would provide a real logistical challenge, and the hexagonal house above the water was no better, some pieces needed for it’s assembly were 9 meters wide. Far too wide to take down the highway on a truck.
So we ran some simulations and here is what we found. The Minispar design had a pitch of only 0.868 degrees and a heave of only 0.835 m/s. This was with one Minispar by itself, without the added stability of being connected to other spars. Best of all, it was small enough to be transported on the back of a truck to anywhere on land that we wanted to take it. With the logistical superiority of the Minispar we finally decided to make it our primary design, locking it in as Design 6.
Another major difference between Design 5 and Design 6, other than the removal of the housing structure and the scaling down for portability, is the introduction of a main ballast tank. The ballast tank, seen in this picture, is about 1/3 solid on the bottom and 2/3 hollow on top. This pulls down the center of gravity on the structure and provides greater stability, while still adding enough buoyancy to keep the platform above water. It also reduces the width of the spar at the water line further reducing pitch. This is why Design 6 is one of our most stable designs to date, in addition to being relatively easy to construct thus allowing us to build it in more locations.
Today we are still refining the Minispar design, and doubtless it will go through a few more transformations as we settle on a build location, sign contracts with producers for our Seasteading Cement, and our supply chain begins to take shape. But as we transition from looking for designs that ‘work’ to looking for designs that ‘work best’ it is clear that we are making great leaps forward for the Seasteading movement as a whole. Within a few months we will have structures in the open ocean, and mass production of our cost effective products can begin in full. After that, the flood gates to ocean colonization will open.