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Pile Driving the Oceans

A forest of long hollow tubes
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As you probably know, a "pile driver" is a gadget that, one at a time, forces an array of long support-struts into unstable ground, so that a structure can be built on top of them. This Idea is about the Oceanic equivalent of that forest of piles.

Each pile is just a hollow tube, perhaps fifty meters long. A temporary weight is attached to one end, so that that end sinks, and the other end of the pile sticks out vertically from the water. Adjacent piles have zigzagging connections between them, at several places along their lengths. Any two piles, if viewed without the water in the way, would look something like a "truss" after the connections were made. Looking at a large group of piles from overhead, the strongest overall arrangement is a triangular grid.
_._._._._._.
._._._._._._
_._._._._._.
._._._._._._
I cannot draw the triangular connections between those rows here, of pointlike pile-ends, but you can probably visualize them.

After enough piles have been connected together, and construction begins on the platform that covers the whole area of the piles, the temporary weights can be removed. This will cause the whole thing to rise out of the water some, so you want to be sure that ENOUGH have been connected before removing any weights, to prevent capsizing. (And of course they will all sink back into the water some as construction on top continues.) More piles can be added at any time to the periphery of the "forest", allowing the platform to be enlarged as needed. An entire City could be built on the ocean this way!

One interesting aspect to this Idea is that if the piles are long enough, say 200 meters, then there will be quite a lot of space between the platform and the ocean. A 50-meter rogue wave would pass entirely UNDER the platform, between the piles!

Now for a few more-technical details. First, the more volume something contains, the better it will float. And when you double the size of something, its surface area (equivalent to the side-walls of the piles) goes up 4 times, while its volume goes up 8 time. This tells us that to get the most float-volume with the least side-wall construction, the piles should each have a quite-large diameter. As an exercise in wild imagination, the ultimate version of such a pile would be JUST ONE. It wouldn't even have a bottom; it would just be a vertical wall that connects in a big circle that was several kilometers in diameter. Roof it over and put your city on top...except that the middle of this disk has a weight-support problem, which might be best solved by going back to smaller-diameter support-piles (trapped air pressure MIGHT be a workable alternative support, but that one lone pile had better not spring a leak!).

The preceding exercise covered one aspect of what is called "economy of scale". Another aspect of that is Mass Production. There has to be some ideal large-diameter pile size that can be fabricated in large quantities on an assembly line. THAT is the size we need for this Idea.

Finally, there is the matter of corrosion control. I don't have anything special in mind, other than maybe a plastic coating over everything under the platform. For this Idea, it suffices that I didn't forget about the need for it.

Vernon, Jul 15 2005

Offshore platform http://www.google.c...en%26lr%3D%26sa%3DG
[normzone, Jul 15 2005]

Truss http://www.euro-lif...ges/TR-BD-Truss.jpg
Here are three tubes connected together; just imagine that end is a top view, and then imagine lots more surrounding and connected tubes. [Vernon, Jul 16 2005]

Tokyo Bay Pyramid City idea http://dsc.discover...ve/interactive.html
I though this design had material strength problems, though. [Zimmy, Jul 18 2005]

Freedom Ship http://www.freedomship.com/
This ship has been frequently cited on other floating city ideas here at the halfbakery. This is the 2005 iteration of its design and concept. [jurist, Jul 18 2005]

Modified floating oil rig for sea launch of commercial satellites http://www.cnn.com/...9910/10/sea.launch/
[ldischler, Jul 18 2005]

Troll floating rig http://www.siemens....ref/ref_troll_B.htm
Way up there! [ldischler, Jul 18 2005]

Marine structures http://www.aas-jako...Marine/marine_e.htm
[ldischler, Jul 18 2005]

[link]






       Well, I'm not going to call [baked], because we can argue that your offshore platform is different from everybody else's offshore platform.   

       And there are other engineering issues to be resolved.   

       But I want you to build it, because then I can dive and hunt underneath it.
normzone, Jul 15 2005
  

       To prevent corrosion, just use a sacrificial metal like magnesium.
shapu, Jul 15 2005
  

       Don't sacrificial anodes just reduce and localize corrosion?
normzone, Jul 15 2005
  

       They seem to work fine on metal-hulled tankers. If they're actually connected to the metal you're trying to preserve, they corrode while the hull doesn't, IIRC.
shapu, Jul 15 2005
  

       + just because, I'd trust vernon with my babies   

       not 'our babies' for those with an over fertile imagination...
po, Jul 15 2005
  

       Why to the pipes have to be steel? Use plastic, or foamy concrete. Or just herd all the plastic milk-bottles and other bouyant crap together in a huge net. By the time you've accumulated a sizeable floating island, I'm sure some kind of marine growth will have glued the whole lot together into a sort of floating reef.
Basepair, Jul 15 2005
  

       I've been thinking about the whole floating city, (heck once you're in international waters; country) thing, and was trying to devise a way for it to submerge in bad weather but piles would make that unnecessary. (+)   

       I understand that there is already a place in the Pacific where the plastic trash of the world has accumulated.
bungston, Jul 15 2005
  

       [normzone], the difference here is that this is a floating platform that LOOKS like the non-floating types. I wanted suomething that could stand up to anything the oceans could throw at it, and I think this can do it.   

       [shapu], I knew about sacrificial anodes, but am not so sure they are the best thing for this Idea. Think square kilometers of surface area exposed to seawater. Sealing the piles away from the water may be more cost-effective in the long run, than constantly having to make sacrificial magnesium, and the electricity to sacrifice it.   

       [Basepair], if you look at the main text, you might notice that I never used the word "steel" anywhere. But I admit that with respect to the sheer quantities discussed, steel may be the least expensive way to go, provided corrosion is dealt with. Plastics likely would be MORE expensive than steel here (made from oil, remember?>, but a plastic coating would be cheap enough.   

       [po]...hmmmm...(imagining all the diapers)...thanks? Oh, wait a minute; I just remembered your babies are of the feline persuasion. Less of a dilemma there; I like cats.   

       [bungston], tell the recyclers! There's money in them thar waters!
Vernon, Jul 16 2005
  

       [scout], I know that there are some floating oil platforms (which still are anchored with cables to the seafloor, to keep them in place over the drilling site). And I've seen some of those big trusses you mentioned -- TOO big for mass production, I think. Also, while the partial flooding you mentioned works fine, I don't like the idea of now exposing up to TWICE as much surface area as before, to corrosive seawater.
Vernon, Jul 16 2005
  

       I have to model this with plastic wall anchors, screws, and bubble wrap.
reensure, Jul 16 2005
  

       before this gets consigned to the bin, I would just like to remind Vernon that 3 of my babies were human not feline.
po, Jul 16 2005
  

       Were?
Basepair, Jul 16 2005
  

       [po], since that's the first I recall hearing about any non-feline babies of yours, I'm not sure "reminder" is applicable. :)
Vernon, Jul 17 2005
  

       edit: (oops! I misread //were?// as //where?//
//widely known to exist// where?
Hong Kong is the only place I could think of that has a floating city (not pier & truss supported, though). I vaguely remember having seen something proposing something slightly similar that can't be made with our currently available materials.
(I found it - link)
Zimmy, Jul 18 2005
  

       [ldischler], I think you are focussing on one piece of the Idea, which is indeed fairly well known. There are no floating platforms out there designed to be expanded arbitrarily, AND arranged so that while floating, the main body of the platform can be as high as 50 meters above the water.
Vernon, Jul 18 2005
  

       I'm wondering if this concept of a floating city would be vastly superior to the Freedom Ship concept, for example, which has the capability of preplanning its itinerary to minimize contact with dangerous seasonal weather patterns and currents. Both concepts are probably similar in size and services offered to residents, but differ in mobility. I think the Freedom Ship plan meets the 50 meter criterion, but it's basically a huge barge, not a legged superstructure straddling the waves. [link]
jurist, Jul 18 2005
  

       //the Freedom Ship concept// Was this called the French Ship concept before the Iraq war?
coprocephalous, Jul 18 2005
  

       //designed to be expanded arbitrarily//

If you’re going to be arbitrary about it, any floating platform can be expanded. As for height, many of them are well above the ocean surface, so that isn’t novel either.
ldischler, Jul 18 2005
  

       [ldischler], by "arbitrary" I meant, "whenever and by however much desired". NO existing platform is designed-from-the-start to be expandable. Mostly because those platforms are built for a specific and not a generic purpose (nor multiple purposes). Also, while many are indeed "well above the ocean surface", that is not necessarily enough as far as rogue waves are concerned. Such a platform as I was describing could be used as an airport in the middle of the ocean. Several at intervals across the oceans could let people in their small private planes go on overseas trips. And any/all could be suitable for emergency landing of the big planes. Simply BECAUSE of being guaranteed-above rogue-wave height, such airfields would always be available. And one interesting aspect of the floating airfield is that its runway can be aligned with the wind, simply by rotating the whole platform.   

       Another variation on the theme, BECAUSE of designed-in expandability, is the chance to build a transoceanic causeway, in affordable stages. First you build an offshore town. Anchor it at intervals with cables to the seafloor. Add airfield. Add causeway to shore. Build another town farther out. Connect it, too. etcetera...
Vernon, Jul 18 2005
  

       This "floating airfield" is called an "aircraft carrier".
ldischler, Jul 18 2005
  

       Read Marshall T Savage's "The Millenial Project," esp. the chapters dealing with the Aquarius phase. He talks a lot about the scales of manufacture that go into constructing a device like this; like [Vernon]'s concept, it is a floater, but Savage's is a wide platform floating directly on the surface; wide "beach" areas and wavebreakers serve to prevent bad waves from causing problems. Smart location away from typically stormy regions does the rest.   

       Savage's idea was to use mineral accretion over charged wire mesh to do the construction; that might work in this concept too. Don't know how corrosion might affect the mesh after all the gaps were filled in, though.
elhigh, Jul 18 2005
  

       [ldischler], an aircraft carrier is not a public facility, nor is it capable of handling 747s. NOR is its flight deck above rogue-wave height. An Idea CAN be legitimately New even if its parts consist of mostly-known stuff. The parts merely need to be diverse enough that nobody put them together before in just that way. Just see the Patent Office for vast numbers of examples!
Vernon, Jul 18 2005
  

       This isn't the PTO, but even there you can't get a patent just because something is bigger and taller and open to the public.
ldischler, Jul 18 2005
  

       [ldischler], you CAN patent something that is designed to be extended to suit multiple purposes, when an original thing was fixed to one purpose.
Vernon, Jul 18 2005
  

       Ah, so you're a patent attorney?
ldischler, Jul 18 2005
  

       [ldischler], no, but I've been interested in inventing for long enough that it behooved me to study the rules.
Vernon, Jul 18 2005
  

       Sounds like an idea, but if you want your it to fly away or explode then it's fine by me :)   

       So, imagine you have your city, but, it is completely sealed off from the underside. Say this is a tropical climate. All that water under neath would become very hot from the weather.   

       The water evaporating under there has nowhere else to go, but up! So it just builds and builds until your city begins to rise, and rock about!   

       Ok, that might not happen but you would have some pressure issues. I suppose slits in the surface could be arranged around your platform's area. People might just use them as garbage disposals though.   

       And what would happen to the sun needing plant life down under the surface?   

       Why are my posts always so long?   

       *sigh* I always have something to say, to much of it, and nowhere to put it. =/
EvilPickels, Jul 19 2005
  

       Trussed piers to a high platform indicated to me that there would be free air movement below.
I bet Vernon would put giant aquarium lights on the platform's underside.
Zimmy, Jul 19 2005
  

       Well I thought that if you had a couple miles of this, you would get a backup in air flow. I doubt any wind would reach all the way back to the mainland anyway.   

       BTW what's a trussed pier?
EvilPickels, Jul 19 2005
  

       Truss braced pier / truss braced column / truss braced pile ... I meant to describe what is shown in the link above under Truss.
Zimmy, Jul 19 2005
  

       [EvilPickels], the main text of the Idea describes two different things. The main thing is a forest of hollow support-tubes. This forest is not sealed away from the outside. A second thing is the notion of one huge wide support "tube", kilometers in diameter. By definition that would have its interior sealed away from the outside. But that notion was also basically rejected in the main text, which sought a mass-produce-able compromise tube size.
Vernon, Jul 19 2005
  

       [UnaBubba], that is not the case in all situations. The alternative I described involves a large area of ocean impaled with these piles. That is, if the piles are 200 meters long but a kilometer-diameter platform is being supported by them, then capsizing becomes rather unlikely. And all growth to make it wider-still merely reinforces its stability. Do note how the main text carefully specifies that the piles be weighted UNTIL a wide enough area has been prepared!
Vernon, Jul 19 2005
  

       One serious problem is that you will have is the entire thing will be easily driven by wind if it - as you say - high enough out of the water to avoid rogue waves. This means that it will be shoved around by the wind. If you moor it you'll have to figure out how to successfully spread this load which would be difficult enough.   

       Further, maintenance would be (perhaps) prohibitively expensive. No matter what construction method you use - steel, concrete. It will eventually require maintenance. What many people do not understand is that anything in the water requires constant maintenance. There's a reason that most large structures in the water are lucrative in nature - Large con-ships/oilers, military vessels, $$-banked research vessels, and oil platforms.   

       Anything motile is drydocked frequently at great cost and oil rigs require a lot of maintenance and overengineering. This is only done because the oil resources they harvest is so lucrative.   

       I think the main problem is really not technical though - but rather an issue of necessity. It would almost certainly be more cost-effective to reclaim a remote desert area such as in the Southwest than build such a city in the ocean.   

       Sorry.
brianr, Jul 20 2005
  

       //to reclaim a remote desert area such as in the Southwest// I think the residents of Devon and Cornwall would be upset by this.
coprocephalous, Jul 20 2005
  

       [brianr], thanks, those are good points. But I think wind loading is not so much of a problem, partly because if the thing is moored, then you can imagine a mooring line from EVERY pile to the bottom of the sea, and so the load on each is the same as if each pile was separately moored. And another thing that can be done is to put a lot of windmills on the platform (and perhaps on piles above waves below platform). Extracting wind energy means it won't be pushing quite so hard, see?   

       Next, I agree that maintenance is a significant issue, which is partly why I at least mentioned a need to deal with corrosion, in the main text. One thing I was wondering, if that plastic coating was Teflon, then would barnacles stick to it? I know that SOME sea critters (certain mussels) can attach themselves to Teflon, but perhaps they are in a mostly ignorable minority. And, Teflon being a particularly insoluable plastic, the overall maintenance costs might end up being manageable.
Vernon, Jul 20 2005
  

       If you are in to wind generation choose a location with a shallow ocean bed not too deep. I mean the ocean floor is miles deep I assume no one is suggesting pile driving that deep. But rather than pile driving do the following find a series of submerged rocks. Place a concrete container similar to a concrete pipe for sewrage (they can be quite big) this would have one end sealed apart from a tiny hole. I am suggesting about 10 feet in diameter with a tiny hole in the closed end of 4 to 6 inces wide. Sink your container in the sea until it covers a rock jutting up. Pump air in until the water is pumped out seal the larger open end with a foam that floats on water pour in 3 inches of your concrete, allow to set. You now have a strong base on which the rest of your concrete can now be poured. The concrete will set and cement itself to the portion of rock sticking up. Completely fill your pilon with concrete or leave hollow if strong enough. Hey presto instant foundation on which to build practically anything. you might even be able to stack these containers in the same manner to go deeper. Build what you like on top.
JNK, Aug 13 2005
  
      
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