User:Vincecate/BallHouse

Idea

Idea is to use a ball shape with HangingBallast to stabilize it. There would be four or more ropes going to a single ballast well below the ball. With a 30 foot diameter ball you could have two good floors and extra storage space. Should be enough for a family. This is probably about the lowest cost structure with enough space that is still safe on the open ocean.

This is very much like User:Vincecate/GeodesicVessel but with no stability from the shape of the structure. This really needs a hanging ballast.

Internal

The geodesic shape should mean you don't need as much, or maybe any, internal bracing. This can open up the inside space and make it cheaper to build.

Materials

If we could make a form for concrete or plastic this could be really cheap. In Anguilla they make forms for poring cisterns where the two sides of the form are connected together by pieces of metal which stay in the concrete. There is a way these are released from the form so the form can be taken off. I think a similar thing could be done to make a 30 foot ball mold work. If so this could be crazy cheap.

Steel or aluminum plates could be done with triangles making a geodesic shape.

Expendable porch

There would be a small concrete entry building on top. Around this could be a wood porch that people would not stay on during a storm. In Anguilla people build simple wood restaurants right on the edge of the beach and just quickly rebuild them if they are destroyed in a hurricane. The wood could also support solar panels. These would be taken inside before a storm. Would use User:Vincecate/Migration to minimize the chance of storms.

Other

Should be very strong, very stable, very safe, and not very costly for the amount of living space.

Could use small strong glass to make portals to let some light in and let people see out some.

The heavy things like batteries should be at the very bottom of the inside space (say below a flat internal floor).

Requirements Analysis

• Safety
  • As long as the hanging ballast stays on it should stay upright

• Comfort
  • Should have a gentle motion on normal days but significant response to large waves.

• Cost
  • Hard to imagine anything cheaper than this that has this much space and is safe in the open ocean.

• Pretty
  • Sometimes functional things start to look nice after awhile. And not every one can afford pretty houses.

• Modular
  • Can make individual family sized units. Could have cable under a line of these so they floated together if you connected a sea anchor at one end and a large kite at the other. Each module could connect to the big cable at its hanging ballast.

• Cargo
  • Since it floats up and down with waves like a boat, should be reasonable to dock a boat next to it.

• Free Floating
  • Yes, could anchor also.

• Scalable
  • Is small enough for one family. The shape could scale to much larger sizes. Geodesic domes scale well.

• Standards

• Mobile
  • Will move through the water easier than most seastead designs but not as easy as a ship.

• Draft
  • Very shallow draft for a seastead if the hanging ballast is winched up. If the waves were small as you approached a harbor it should be safe to winch up the hanging ballast. Could lower the ballast onto the bottom in the harbor. If the ballast could be split into 4 or more pieces it could be stable like a tension leg structure when parked in shallow water.

Experiments

Used a 36 cm (14.2 inch) diameter buoy with 20 lbs of steel weights. At 1:25 scale this is about a 30 foot sphere. These videos should have been slowed down by a factor of 5 but are really slowed down by a factor of 4.

The first video is with about 4 feet of rope in waves that are a few inches (6 inches simulates 12.5 feet). This was shot near the end of the pier in Island Harbor Anguilla. This swings back and forth too much. Experiments on later days with longer ropes work much better.

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Experiments 2 - deep water in Shoal Bay

The next 4 videos were shot on Aug 28, 2008 after swimming to deep water on the other side of the inner reef at shoal bay. I estimate the biggest waves are simulating 50 foot waves, which is bigger than I expect to ever see if we use migration.

The first video below is with the 20 lbs of weight tied close below the ball, maybe 1/2 foot.

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The rest of the videos on this day are with 23 feet of rope between the ball and the 20 lbs, in the same big waves as the video above.

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During this next video I was drifting closer to shallow water so stopped early. There are a couple times when the ball seems to tilt a bit. It may be because the weights had touched bottom and the tension on the rope was reduced. But either way, this ball is still doing a good job of keeping the topside up in really large waves.

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This next shot if fun because there is a jellyfish in the upper-right part of the shot. It is also interesting because in about the middle of the clip we get the underwater view of a breaking wave hitting and tipping the model.

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Experiments 3 - deep water outside Island Harbor

The videos in this section were shot from a kayak on Aug 31, 2008. I took the net off the buoy and put some black lines on to make it easier to see how much the buoy tips with the waves. It had the same 23 foot rope used in the Shoal Bay experiments. These were shot outside the reef north of Island Harbor Anguilla. The kayak rudder does not work when you are nearly standing still so peddling did not work so well. I could not use the paddle while keeping the camera aimed, so that was not good either. I tried giving my 4 year old the camera, but in hindsight, I really should have explained the goal of keeping near the buoy and had him use the paddle while I did the camera. Anyway, these are mostly not close enough to see how well my water-level with a new block inside to dampen the sloshing is working, but sometimes. I would call these simulated 40 foot waves, which is more than I think we will see if we use migration.

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In this next video we got close enough at times to really see the red water moving around. Even though the buoy is staying very level, the waves are accelerating it sideways and so causing the red water to move around. Now these are simulated hurricane conditions, and not normal weather. If you were in a small bunk with sides on it or in a seat with a seatbelt, you would be fine.

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This next video was shot by Tern, my 4-year-old, while sitting on the front of my kayak. The a lightweight boy on the front moves up and down more than a big dad in the middle. But it is still interesting.

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Full Scale Ball House in Plastic

I think it would be reasonable to make a 30 foot ball out of HDPE plastic. If this has "carbon black" in it the sun won't hurt it. I am thinking that if the plastic was 1 inch thick it would be plenty strong enough. A ball is a strong shape as the sides sort of have arch type support in both directions. Think of how strong an egg is when you try to squeeze it in your hand.

The density of HDPE plastic is just under that of water. If you buy the HDPE pellets by the ton, the price is about $1/lb. So a 30 foot ball that was 1 inch thick might weigh about 15,000 lbs and cost about $15,000 for the raw plastic. It may even be that 1/2 inch is thick enough. This would be a very low cost seastead.

You could have an inner and outer mold connected by bolts to hold the right spacing between the molds. After pouring you take out the bolts and the molds come apart in sections. Then you plug the holes in the ball with HDPE plugs (fusion weld these in).

Another possibility is related to how they wind on the plastic for large corrugated plastic pipe. We could go around and around making a ball instead of a pipe. Maybe we put on a two inch wide strip of plastic each time we go around. Might take a machine most of a day to make a ball but this is not bad.

My favorite way is to have a big ball rotomold out of aluminum. This 30-foot aluminum ball would be set on some wheels so it could be rolled in different directions. Probably 3 or 4 wheels with 1 or 2 that can turn and an electric motor on one or more. If we put the HDPE pellets inside, start rolling the mold, heat it up, and keep rolling the mold while it cools down we can have a big plastic ball when it is done. This "rotomolding" is how most kayaks are made so easily that they can sell as little as for $240. The mold would have to come apart in sections so we could get the plastic ball out.

Looking to see how large a plastic ball I can find I see a 90 inch ball.

Low Cost Design Champ

The ball does not heave up and down like the pipes/cylinders/spars do so it would not require heave plates. Having the ballast rope attach to the bottom of the ball provides enough stability, no truss is required. The experiments show that this design does well even in 50 foot waves. A ball shape is strong for the amount of material, whatever that is: plastic, concrete, aluminum, or steel. So I think for small single family seasteads that are safe on the open ocean that this is the low cost design champ. If you think there is anything cheaper please post in the discussion for this page or on the Engineering forum.