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WaterWalker from used utility poles and big buoys

Home Forums Archive Structure Designs WaterWalker from used utility poles and big buoys

This topic contains 65 replies, has 12 voices, and was last updated by Profile photo of Dil Dil 5 years, 10 months ago.

Viewing 15 posts - 16 through 30 (of 66 total)
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  • #4215
    Profile photo of vincecate
    vincecate
    Participant

    In a production WaterWalker style seastead, I think aluminum would be the material chosen for the legs. Not sure if a truss, I-beam, box-beam, or circular tube, or something else would be the best choice. Things like making steps up the legs, wind resistance, cost, strength, corrosion resistance would all have to be taken into account. You would really like it wider in the middle and thinner at the edges. With a truss that is easy to do. Could also have two sort of cone shapes half the length with the bases bolted together. Maybe each 50 feet long and 3 feet wide at the base and foot wide at the thin end. This is my best guess.

    For a prototype that I am paying for on my own, cost is very important. I am just going to be using this 1:5 scale model a few times, my guess is 1 to 5 trips. So optimizing weight, reducing maintenance, increasing load capacity, etc all take a back seat to lowering cost. There was a steel 3-inch pipe that seemed strong enough but it was probably nearly twice the weight of the square tube I bought and almost 3 times the price. I really have a somewhat limited selection of materials here. :-)

    My guess has been that either I can not find a reasonable aluminum tube/pipe/beam on this island or that it would cost more than I want to spend. But it is worth at least a few phone calls, so I will do that. But at 48 lbs my 20 foot steel box beam for $53 is not too bad. Aluminum might beat it by making 30 or 40 foot legs possible, but probably not at a price I want to pay on my own. Because of shipping, duty, and limited competition, prices here are usually nearly double what you can get in the US.

    #4221
    Profile photo of
    Anonymous

    Good points. Using a custom tapering/conical beams or tubes would probably be the very best solution. You might have to produce a large number of sesteads for this to make economical sense though. I don´t think wind resistance etc will be that important. Steps and stuff can always be arranged somehow. Strength per cost is the big issue I´d guess.

    4 OD x .125 wall x 3.75 ID 6061 Aluminum Round Tube 24ft was $233 at metalsdepot.com. Pricier than I would have thought… Haven´t really researched that much though.

    The above is mostly about making a usable full size seastead, by the way. I realise prototype making has different constraints such as availability.

    #4350
    Profile photo of Jesrad
    Jesrad
    Participant

    I can vouch $200 for funding this.

    Remarks on the physics: having a low net positive buoyancy is a good thing, because it dampens the heave and stresses from waves a lot. Ideally we should use a lot of cheap, inefficient floatation material.

    Remark on the design: why not suspend the “habitation” to the top of the tripod instead of fixing it on top of it ? It’s probably cheaper to make the legs a tiny bit longer and save a lot on the connection solution.

    #4355
    Profile photo of vincecate
    vincecate
    Participant

    >I can vouch $200 for funding this.

    Thanks! Joep has vouched for $300 (an earlier estimate) but really a total of $500 looks more reasonable now.

    >Remark on the design: why not suspend the “habitation” to the top of the tripod instead of fixing it on top of it ?
    >It’s probably cheaper to make the legs a tiny bit longer and save a lot on the connection solution.

    Yes. My current plan is to hang two lawn chairs from the center. I also think I will have 4 legs instead of the 3 in the 1:25 scale model. Makes it easier to carry 2 people with the 4 barrels.

    The top will have pairs of legs joined with a gate hing and then rope between the two pairs and down to the lawn chairs. Also some ropes to the sides. I will have ropes making a cross near the bottom as well as ropes going around the 4 legs.

    Not sure yet if I will just strap one barrel to each leg or if the leg will go below the barrel and a rope go up to the barrel. Also not decided if the ropes near the bottom are underwatter at the ends of the legs. I am going to measure the force needed to move one barrel in the pool and the force from my kite. If making 1 MPH looks easy then ropes probably will be under water. If not then barrels tied to the legs and ropes just above them.

    Will have it built and probably a maiden voyage in the next couple months.

    http://wiki.seasteading.org/index.php/User:Vincecate/WaterWalker2

    — Vince

    #4611
    Profile photo of vincecate
    vincecate
    Participant

    I bought the rest of the stuff for my 1:5 scale model today and should put things together in the next day or two. Also put up couple sketch-up images of the model. Drawing is not exactly right (center column will go down to platform) but close.

    http://wiki.seasteading.org/index.php/User:Vincecate/WaterWalker2

    #4612
    Profile photo of Joep
    Joep
    Participant

    Just 5 of these and we’re finished :) Happy building in 2009!

    #4614
    Profile photo of
    Anonymous

    That looks good.

    You might consider filling the steel beams with concrete or something to make them even more rigid.

    #4616
    Profile photo of vincecate
    vincecate
    Participant

    I thought some of filling them with foam. This would provide a little extra flotation. It would also mean that if everything fell apart nothing sank to the bottom. :-)

    I have a Ford Explorer. The 4 empty metal beams are a lot of weight for the roof rack. I am sure I would break something if they were full of concrete.

    — Vince

    #4626
    Profile photo of vincecate
    vincecate
    Participant

    We got rain Thursday and then power went out Friday. So construction of my seastead to ride on has been delayed a bit. I wrote up a section on my design decisions (some of which have changed in the last 2 days). I would appreciate any last minute advice on these that anyone has.

    http://wiki.seasteading.org/index.php/User:Vincecate/WaterWalker2#Design_Decisions

    #4627
    Profile photo of
    Anonymous

    Going from 3 legs to 4. I did this because it gives me a wider base and lets me use 4 of the cheap barrels I have available. With this I am sure I can carry 2 people and maybe more. Makes structure a bit more complex.

    With four legs one could end up out of the water on occasion. This might result in shock loads. Perhaps a remote possibility only in extreme conditions but worth mentioning at least. Three legs is a more stable layout.

    How to join the legs together at the top. With 4 legs the 4 hinge method on a central column seems good.

    If you make something like a four-pronged (or three depending on the number of legs) grappling hook you could just hang your “habitat” from that. This gives movement in both axes as well, not just one like a hinge.

    I contemplated just welding them together but that would probably put bending forces on the legs which also would deviate from tensegrity. Probably not good.

    With 4 legs it makes sense to have diagonal ropes between the legs but I think this is not really needed. Without the diagonals opposite sides can move in or out while other pair does opposite. Should be limited range though as weight is transfered to legs coming together. Might reduce passenger motion. A WaterWalker with moving legs seems fun to try. Makes tying the platform not so easy, but might be OK without ties.

    Possible drawback four the four-legged version again…

    Ropes out of the water or at ends of legs? If the ropes are out of the water there is less drag for the structure moving through the water; however, the stress on the leg is more. If the ropes are in the water they can help to attract fish. Can also use the same attachment point used to tie barrels. Expect to tie at ends of legs.

    Ropes at ends. If not you are deviating from the lovely tensegrity philosophy. I don´t think drag is such a big issue at the speeds you are planning on traveling. And whenever you are not trying to travel anywhere drag is good.

    Height/width ratio. If the structure is wider it is more stable, but there is more stress on the beams and ropes. With ropes at ends there is less stress on beams and I can make structure wider before breaking anything. I also think there is less risk of trouble from leaving off the diagonal ropes if the structure is very wide.

    Seems to me like this will be decided by other factors like the space you want for occupants or available material more than any optimized structural strengths. If not just go with a nice even number like 90 degrees on the summit. That seems to work for a lot of pyramids anyway…

    How to make platform for people. Don’t want it to be too heavy but people need to be able to hang out for the whole trip. Decided on a small seat at the very top and a 4′ by 4′ platform about 4 feet down from joint. Can lean on the legs while standing. Attaching both with L brackets.

    Use many ropes from the top to spread the weight around. Some kind of steel truss structure with plywood for a floor probably could be strong and pretty lightweight.

    How to attach the barrels

    Strap barrels along end of the leg – no movement or danger of hitting leg but bigger waterline area

    Probably more difficult to get a good fastening solution. Waterline area doesn´t seem like a big deal to me. You mean this could change the bobbiness factor (for lack of a better term) of the barrels?

    Tie them so they float horizontally with tail fin so line up in direction of movement – could reduce drag when moving through the water. Complicated with what I have.

    Sound totally ridiculous. Demands more rope to barrels to keep distance to legs which will make structure sit lower in water.

    Tie them so they float in normal barrel orientation (vertical) – minimizes waterline area – some danger of barrel hitting leg. With ropes and legs in the water heave should not be too much of a problem. Choice I made.

    As long as the barrels are decently loaded they shouldn´t move about too much. I guess the question is exactly how much rope there needs to be to the barrels to keep them away from the leg. Perhaps you could use a pulley to get the rope up to the platform to fine tune this enroute. A simple winch perhaps could be used for this.

    Make sure you have some kind of emergency stop knot on that rope though. It would suck to lose a barrel…

    #4628
    Profile photo of vincecate
    vincecate
    Participant

    With four legs one could end up out of the water on occasion. This might result in shock loads. Perhaps a remote possibility only in extreme conditions but worth mentioning at least. Three legs is a more stable layout.

    The momentum from a wave will not throw a barrel on its own out of the water. Without the diagonal ropes the rope around the outside will have about the same tension everywhere. With the angle of the beam the tension on the rope will push the end down. The structure is not rigid, so I really think there is no way it could lift any part out of the water. Without the diagonals it is hard to even see a shock load possibility. It is like we have 4 triangles connected at the edges and it can wobble some. But the lowest energy state is with the bottom like a square.

    Ropes at ends. If not you are deviating from the lovely tensegrity philosophy. I don´t think drag is such a big issue at the speeds you are planning on traveling.

    Yes. It is fun to be able to stay a tensegrity structure.

    Seems to me like this will be decided by other factors like the space you want for occupants or available material more than any optimized structural strengths. If not just go with a nice even number like 90 degrees on the summit. That seems to work for a lot of pyramids anyway…

    I think I will have a wider angle at the top than 90 degrees.

    Tie them so they float horizontally with tail fin so line up in direction of movement – could reduce drag when moving through the water. Complicated with what I have.

    Sound totally ridiculous. Demands more rope to barrels to keep distance to legs which will make structure sit lower in water.

    I think a production version could be made with basically a boat at the end of each leg. Then it could move easily through the water. The leg could attach with a hinge that let the boat rock front to back but not sideways. This would not put much torque on the leg.

    As long as the barrels are decently loaded they shouldn´t move about too much.

    The worry is just that a wave hitting one barrel moves it into the leg. Originally I was going to use ship buoys that were nice and soft. If one of those hit a leg I would not worry. These barrels are hard but so much cheaper that I am using them.

    – Vince

    #4630
    Profile photo of vincecate
    vincecate
    Participant

    I put up some pictures showing how construction is coming along for my ride-on seastead. Some bolts were a bit long and we needed extra padding washers, so we ran out of washers. We would have had it up in the yard today if not for that. Should have it together in the yard tomorrow (Tuesday) and hope to have it in the ocean Wednesday.

    I changed things a bit again (even since one of these pictures). Going to just suspend the platform by ropes so as not to risk putting too much torque on the hinges. This is how the sketch-up drawing had it.

    http://wiki.seasteading.org/index.php/User:Vincecate/WaterWalker2#Construction_Progress

    #4636
    Profile photo of vincecate
    vincecate
    Participant

    We raised the seastead model up. You can see a picture of me on it in my yard. Am I the first human on a seastead? We also practiced with 3 kites today. Two of my kites had not been used in 10 years but they still flew fine. I still think we are launching tomorrow, assuming winds are normal.

    http://wiki.seasteading.org/index.php/User:Vincecate/WaterWalker2#Construction_Progress

    – Vince

    #4637
    Profile photo of livefreeortry
    livefreeortry
    Participant

    Is that cool or what?? Can’t wait for your trial..

    Aren’t you going to attach the platform to all the legs? Also, in the things to bring on maiden voyage, maybe you should include helmets, since you’re going to be quite close to a few hard objects?

    #4638
    Profile photo of vincecate
    vincecate
    Participant

    >Aren’t you going to attach the platform to all the legs?

    Yes. Truth is I ran out of rope. :-) Will have it though before we leave the beach for the open ocean.

    >Also, in the things to bring on maiden voyage, maybe you should include helmets, since you’re going to be quite close to a few hard objects?

    I think I will put on a safety rope connecting the beams at the top in case a hinge fails.

Viewing 15 posts - 16 through 30 (of 66 total)

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