Someone help me figure this out – PLEASE!
September 7, 2011 at 1:33 am #15286
Berg w/ hydroturbine electrogenerator:
“Leadership and do-ership are not the same thing”September 7, 2011 at 2:36 am #15287
Lateral Force = Density x Gravity x Height.
King Shannon of the Constitutional Monarchy of Logos.September 7, 2011 at 12:33 pm #15305
starting to look a bit like what Octavian proposed a while back…
“Leadership and do-ership are not the same thing”September 7, 2011 at 3:57 pm #15307
Remember, @ sea, K.I.S.Shredy,…If you want to submerge the burgstead you are opening not a can, but a BIG BOX of worms,…As I told you before, you won’t be able to have the “green” area on top deck as pictured above and the onboard systems, balast tanks, pumps, etc,…everything “attached” to submerging that baby will cost you an arm and a leg and it will become a logistic nightmare.
Your choiceSeptember 7, 2011 at 5:13 pm #15309
You’ve also got to constantly regulate your depth somehow unless you only intend to only flood your ballest tanks to just the (+) side of nutral boyancy. Of course that would nullify the whole point of submerging to avoid storms wouldn’t it?September 7, 2011 at 9:24 pm #15315
Ellmer thats a good point and one u have mentioned before. in fact i worked that into some older models with pop-ups at the corners. what im thinking here is that the huge solid weight on the bottom and the air in the upper part will work together to keep it stable.
“Leadership and do-ership are not the same thing”September 7, 2011 at 9:26 pm #15314
the way to submerge stationary and stable with no engine and trim surface need is how Mighty Servant does.
Small buoyant bodies stick out and stabilize the structure – the technique is called hang on the snorkel in military sub ambient.
German u-boats used “hang on the snorkel” to pass the straight of Gibraltar with the ocean currents in total silence all engines (incl. electric) shut off.
Stabilize a WW2 u-boat just with the bouyancy of the snorkel tube is technically challanging as you can stick the tube out just so much that it is still camuflaged by the waves.
For civilian use in a submersible ship or seastead the “snorkel tube” can have the size of a tower and stick out several meters – so the presumed “additional engine and sistem need” for submerged is probably a mis-perception. If the ship shape and configuration is proper you can submerge with a simple ballast pump – nothing else is necessary.
concretesubmarine.comSeptember 7, 2011 at 9:35 pm #15316
a deep ballast center keeps you on even keel at dive but does nothing to keep a stable dive depth…
just a thought – use the deck as drydock instead as a garden…and…have you thought about how much ballast water you will need to achieve the buoyancy changes you paint in the pictures (the same as the displacement of the structure) and that the required volume of the tanks would eat up the living space completly…September 8, 2011 at 12:21 am #15318
yes – PLEASE READ –
the LAST pictures i posted of the new design show the water level to be just right for the boat to pull into the garage. that is ballast level 0. no ballast at all achieves exactly that level according to my “Bergstead Displacement Calculator” spreadsheet. AND i spent some time to get just the right balance so that when the ballast tanks are filled up it will sink. i dont know how deep it will go, but it has a few percent more weight filled up than the displacement needed for neutral buoyancy.
“Leadership and do-ership are not the same thing”September 8, 2011 at 3:10 am #15324
this is how much ballast is needed. remember that the pyramid is all solid concrete. i’ll check it again tommorrow but thats where my spreadsheet tells me this needs to be.
“Leadership and do-ership are not the same thing”September 8, 2011 at 5:39 am #15326
Okay, so considering that as a flat surface, are not going to be utilizing any compressive-strength, as all that pressure is now pulling the concrete apart, so we look at the tensile-strength.
Tensile Strength of concrete is 3Mpa http://en.wikipedia.org/wiki/Tensile_strength while atmospheric pressure is 101KPa, at 40 meter’s depth it’s 500KPa, in rock-climbing, we like to have a safety margin of at least 10, so would recommend max pressure of 300KPa, that implies the bottom of the berg should stay above about 17m depth.
Now I’m assuming that there has to be some kind of thickness or cement-mix that would give it the illustrated tensile-strength, though at this time I’m not sure what it is.
In any case this is a rather simplified perspective, though it does inject some math in.
calm aware desire choice love express intuit moveSeptember 9, 2011 at 12:26 am #15343
You should avoid hanging that pyramid the way you shown it, meaning by means of cables and bolted to the underwater portion of the hull. First, in time, whatever fitting you will use they will corrode and fail. Second, they will be subjected to a lot of stress forces caused by the inertial mass of those 2 bodies there, specially in heavy seas. IMHO.
To avoid such potential damaging problems, I think you should make the pyramid part of the hull. If you do so and ballast the bilge (the top of the pyramid, since inverted) you will achieve more or less the same stability performance (few feet of less metacentric distance won’t matter that much related to the whole mass of the structure).September 9, 2011 at 12:51 am #15354
well maybe the connections between nylon rope and concrete could be some gargantuan threaded eye bolts. and when these eye bolts are tightened into position, they somehow lock out any water from getting inside the threaded area – by using a rubber seal. that way after 15 years u can change the eye bolts and put new ones in. or maybe just make them out of nylon?
i dont understand why, earlier, Ellmer said that i should scrap the recreation space on top. we talked about that a long time ago and i said that nothing on top was actually “real”. no real plants. the “grass” is astroturf. the tree is plastic with metal running up the middle. its all there just to create the “ambiance” and the “wow factor”.
once the design is thoroghly spec’ed on paper, a builder just needs to buy all the materials and build it exactly as the plan reads. all of the materials would be bough from external vendors and shipped to the building site. these include; the special concrete, metal framing supplies, blocking, electrical stuff, plumbing, ALL of the mechanical systems, windows…
it was Emmetts idea to hang the dead weight really low, and i def agree with him. its like Wil said, we need to offer a comfortable living space. it is high on the priorities list if we want these to be marketable.
“Leadership and do-ership are not the same thing”September 9, 2011 at 4:24 am #15382
I do still support the idea of having a low keel/counterweight, but ONLY if it is connected by RIGID connecters. Having a non-rigid connecter does technically lower the center of gravity, raising the metacentric height, but not NEARLY as much as if you had a rigid connection system. You could have a mile long rope system and it would help little more than having 20′ long ropes.
If, though, there is some math I am ignoring in my calcuation of this, or for some other reason you decide to keep the rope systems, it is quite easy to avoid corrosion. Simply use Industrial Plastics for your eye bolts rather than metal. You can then just set the plastic eyebolts into the concrete when you cast the structure itself, and no problem. I believe you will find that many industrial plastics have strengths that will far exceed the requirements you need for this application.
As to the space on top, I think it is worth working into the final models. Even if you have to build a somewhat expensive segmented plexiglass covering to keep your plants and deck chairs dry, people crave access to “open air” and greenery. It is something that, after a few years of rea seasteading, I believe will become expected on any proposed seastead, simply due to human nature leaning towards wanting greenery. My opinion, but a very strong one.September 9, 2011 at 4:55 am #15388
the pyramid will be very heavy, nylon rope might snap in the first storm. You need steel cable. If using nylon rope, the only way to attach it to an eye bolt is to make an eye splice http://www.animatedknots.com/splice/index.php and use a metal thimble (Nautical . a metal ring with a concave groove on the outside, used to line the inside of a ring of rope forming an eye.) for protection agains chafing. Since you will connect at the 4 corners, you will have 8 potential failing points in the eye splices, another 8 in the eye bolts and 4 in each rope for a total of 20. If the pyramid is part of the hull you will have 0.
Also, keep in mind that this whole “hanging process” have to be done on land, before launching. (because of the eye splicing of the rope into the eye bolts). If you loose the pyramid 500 nm offshore, you’d better be ready to peel some large bills: fabricate another pyramid, hire a boat to ship it to the bergstead’s location and hire some divers to hang it down bellow (and make sure that they know how to splice an eye under water
But you do as you wish, it’s your project
PS. No plastic will cut it. The UV and corrosion will eventually get to it. Stainless steel.
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