We are working on a seastead design. The goal is to design our seastead such that all the parts can pack into a single a High Cube 45 foot container which has: width 7.7 ft height 8.9 ft length 44.6 ft max weight: 62,000 lbs (rated bouyancy at desired waterline is 27,500 lbs and we hope structure is enough under this that humans and their stuff can fit) Above the water there will be a big equilateral triangle frame, 44.0 feet on a side. The triangle frame is also the wall of the living area and will be 7 feet high (floor to ceiling). It will be enclosed and the whole inside the living area. Around the whole outside of the wall, except where the dinghy is in the back, will be a 3 foot wide walkway and railing that is bolted on and has some diagonal supports from below bracing to the wall (so walkway is 1 food higher than bottom of the wall). The walkway will have an aluminum grating that would let a wave pass through but you can walk on. Also two doors on the back side, one two feet in from left and one two feet in from the right side. There are 3 legs/floats/foils/wings/keels that provide the buoyancy, so it is a bit like a trimaran but with a very soft ride. Each leg/wing will 14.5 feet long and have a NACA 0040 foil shape with 8.5 foot chord except that the last 0.5 feet of the thinnest part will be cut short, so with foil does not come to a point at the trailing edge and fits within 8.9 feet hight of container. But the buoyancy is very close to that of an 8.5 foot chord foil. Each of the 3 legs will be attached to the underside of the big triangle near one of the 3 points. The center of the thickest part and going 1.5 feet in all directions from there will be within the area of the triangle, but within that constraint, each leg will be as close to the point of the triangle as possible. The legs will go down so that the lower half is in the water. This makes for a bit of "small waterline area" similar like a small oil platform but one that can move through the water easier because of the foil shape. It is not an extreme SWATH design as a 1 foot change in water level is about 1/7th of the total buoyancy, so still significant change. The 3 legs will all be parallel with the blunt or "leading edge of the wing" side facing forward so it is lower drag when moving forward than a typical cylinder on a semi-submersible platform. Each leg will be 50% under the water (so 0.5 * 14.5 feet) and the top 50% out of the water. On the top half of the front of each leg, so the top half that is out of the water, will be a built in ladder. The reason for these sizes for the triangle and legs is so they can pack into a container nicely and shipped to a shipyard anywhere for assembly. Imagine the 3 legs end-to-end with thin/trailing-edge of foil up and leading edge down on the right side of the container. So the right 3.4 feet of the container (width of legs) is used by the 3 legs. Then the 3 frame/wall sections will be upright (so 7 feet high) next to each other along the left side of the container. I am not sure the width of the walls but if they were 10 inches wide then 3 widths is 30 inches and some extra is 3 feet on the left side. There should still be lots of room in the center of the container for all the other parts. Connecting the mid points of the walls both at floor and ceiling level will be structural beams that make another triangle 22 feet on a side. Then all the remaining spans will be less than 22 feet. The rest of the floor and ceiling will be small pieces that are bolted in. On top of the roof there will be solar all over. With batteries and electric thrusters as the main propulsion system. There will be 6 RIM drive thrusters of 1.5 foot diameter, one on each side of the 3 legs/wings about 2 feet up from the bottom. These RIM drives will be all be fixed orientation to provide forward thrust. It will use differential thrust to turn. For slow movements in tight areas like harbors it can reverse thrust on one side and forward on the other to turn in place. There will be a conduit/pipe welded to the back of the trailing edge to take electrical wires down to the thrusters. There will not be any "through hulls" in the legs. The legs will also have multiple airtight compartments each for safety. Behind the back near the center will be two supports going out and 2 ropes going down to a dinghy. The dinghy is a 14 foot RIB boat (deflated for shipping) with an electric Yamaha HARMO outboard. It is sideways against the center of the backside of the living area. When the seastead is moving forward the dingy is shielded from the wind by the living area. On the lower part of each leg will be several bolt on heave plates. These will help dampen the response to waves. About 25% of the displacement will be for LiPo4 batteries which will be put low in the 3 legs. Each leg will have its own charge controller and inverter so there is triple redundant power on the seastead. Also, the thrusters for a leg will get power from that leg's inverter or batteries. So the 3 pairs of thrusters will have independent failure modes as far as power. When the seastead is going to be staying in one place for awhile, we can put down 3 helical mooring screws and give the seastead tension legs so it becomes nearly stationary when parked. Near each corner there will be a pair of helical mooring screws with a motor unit between them. We only plan to do this in the Caribbean where tides are very small and in protected places where the saves are small, so pulling down 3 feet will be sufficient to never go slack. Two seasteads will be able to connect together with a walkway, one behind the other, so that while underway people can move between seasteads, enabling a real community. The two computers for the two seastead will both work thrusters to minimize the movement of the walkway, particularly when warned that someone will be on it. We are working on a design to quickly put in and out helical screws for a prototype 1/2 scale version of the above seastead. This is to experiment with the tension leg idea in shallow protected water. We would like a proceedure that works for the 1/2 scale prototype but also should work for the full scale. The design goal is a 1000 lbs load on each of 3 screws. We assume the seastead has 400 lbs thrust. The current idea is to use single 6 inch helix mooring screws with hex shaft that is 8 feet long and has a 1 foot diameter capstan wheel that can slide up and down the hex shaft. What would you recommend so that it slides up and down well? There will be a float attached to the mooring screw eye to keep that end up, but still let the other end go to the bottom. It will be stored sideways on supports outside the railing. Before releasing into the water a long rope will be wound around the capstan the right number of times (mabye 4) and there will be some spring loaded thing that keeps the ropes in place before there is tension on them. When in in the water one person will use the dinghy to make sure it is in the right position and vertical. There will be some extra rope, maybe 80 feet, that goes from the capstan to the seastead and lots rope, maybe 200+ feet on the other side of the capstan. The surface of the capstan where the rope is wound around will have a texture to it to make the rope less able to slip. The rope will be very long so just the resitance of pulling it along the ocean floor seems enough to start the "capstan effect". The seastead captain then drives away, which spins the capstan wheel, which drives in the screw. When the mooring eye gets down to the capstan wheel the capstan wheel can not slide any further along the hex shaft and is forced into the sand if it tries to keep turning but that makes it have lots of resistance, which makes the rope release from the seastead. The capstan wheel slides down the shaft and rests on or near the seabed while the shaft sinks through it, the sideways pull happens at ground level. The wheel is heavier than water and the seastead will be far enough away that the upward part of its pull vector is not enough to lift the wheel. We rather have a longer rope to reduce the angle than a heavier than necessary wheel. Estimate the weight of the wheel and how far out the seastead has to be. Now, on second though, I don't really think this is an issue when screwing in. The torque on the shaft will and the shaft going down will tend to pull the capstan down and it will take the force against the sand to make it slide over the shaft. I don't really think we need to depend on the weight of the capstan for any reasonable friction along the shaft for insertion. What I am really worried about is when we are extracting the screw that the capstan will move up with the screw instead of staying down by the bottom. I am not sure how to ensure it stays down. One idea is to have the seastead go slack many times during extraction so the capstan can side down the shaft, then resume pulling. This would take longer but maybe not too much. For normal operation we want the capstan wheel to slide over the sand, so some rolly/sliding thing should be on the bottom that just handles the normal weight of the wheel and enough force that it will slide over the shaft as the shaft goes down. But when it starts to get into the sand this first thing should compress and a second layer of pegs/feet on the bottom of the wheel come into play. These will be at an angle so it stops the wheel when trying to spin into the sand but offers little resistance when turning to go up. Each of the 3 mooring screws will have its own capstan wheel which can't come off. Given how far away the seastead has to be before we start turning the wheel, and how many times the wheel needs to turn to screw in about 7 feet, and how much rope is used per turn, how long a rope is needed? Note that the same rope and seastead will be used for each of the 3 mooring screws in series. Please flesh out the idea and check if everything can be made to work. Assuming we are in typical Caribbean sand, will the mooring screw be strong enough for 1000 lbs load straight up? Normal mooring screws just have a coating but the way we plan to use the screws, putting them in and taking them out many times, a coating could get sanded off. So we want to have marine stainless steel mooring screws. What do you estimate it would cost for 3 of these, in marine stainless with capstan wheels, if we ordered just 3 and also if we ordered a batch of 30 from someplace in China? How heavy will each helical screw with capstan wheel be? There will be a 20 foot floating rope in the eye of the mooring so it is always easy to grab on the surface of the water. To remove the screw it seems a swimmer will have to go down and put a rope around the capstan 4 times and put the spring loaded thing to hold the rope till tension starts. After a crew has done this many times, in shallow water like 8 feet, how fast do you think two people (one in dinghy and one in seastead) could put in 3 mooring screws or take them out? If we later want to scale this mooring screw proceedure up to the full scale scale seastead, with 8000 lbs of pull rating on the screw. I am thinking double the helix diamter to 12 inches. Make the shaft go from 8 feet to 12 feet. The capstan diameter from 12 inches to 24 inches. The seastead thrust from 400 lbs to 2000 lbs. Rope length probably around double. Do these numbers work? What is your estimate for the weight of the screw mooring and capstain total? I am thinking maybe triple the lbs. Will probably store the device laying sideways just outside the railing on a couple supports. Can have a pulley system to lift it into place. Does it seem like it will still generally be a workable method for the full scale seastead? We can probably develop device that will be easier to use but they will cost more, so something like this will probably be the base offering and another system an optional extra. Customers that don't use tension leg anchoring, or don't move often, will be ok with base system and someone who moves every day might be willing to pay for a more automated method.