Seadome Design

Discussion in 'Boat Design' started by Novice Boaty, Apr 18, 2013.

  1. Novice Boaty
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    Novice Boaty New Member

    Hey, just some preliminary plans for a permanent concrete seadome structure. Just working through the calculations for concrete thickness, weight distributions, displacement etc etc so this is just a first pass design.

    Thoughts anyone?
     

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  2. Petros
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    Petros Senior Member

    how deep do you intend to build this thing? As you go deeper you loose sun light real fast and there is not much that will grow at only about 40 ft depth. how will you get in and out of it? where will freash water come from, where will the waste go?

    Why? building a home on land is far cheaper, even including buying water front property.
     
  3. philSweet
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    philSweet Senior Member

  4. MantaRay
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    MantaRay Junior Member

    I love the idea of a self-sustaining off-shore habitation unit. First time I saw one was the Lilypad.

    I guess the dome would be inshore? I guess your dome will have a geodesic structure? I guess it will distil salt water to make fresh water? I guess it will produce bio-diesel using gasification/pyrolysis?

    Where will the waterline be? If the water line is high up how would accidental flooding be prevented without tipping and sinking the dome? Can/will it be anchored? Is that a propulsion system on the second deck? How about using energy storage from renewable energy such as solar and wind instead? If so, look into marine/solar Stirling Engine unit - the temperature differential will provide many KW.

    I like the novelty (also especially how the upper deck ceiling can open up), it will be interesting how this project progresses.
     
  5. PAR
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    PAR Yacht Designer/Builder

    Welcome to the forum.

    This isn't "a self-sustaining off-shore habitation unit", but in reality is a vessel, so you'll have to jump through the usual hoops in this regard. If you have to ask about displacement, then you'll need considerable study before anything approaching reasonable assumptions can be made. Since it's propelled, you'd be wise to make the vessel, well boat like. A disk or saucer shaped craft isn't going to do much very well, except look interesting. A sphere is about the worst shape you could employ. If propulsion is just to occasionally move the puppy, then a tow boat might be a better, certainly cheaper and less complex path. Naturally, you'll need a 7 possibly an 8 figure budget.
     
  6. MikeJohns
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    MikeJohns Senior Member

    They are called minimalist cruising yachts aren't they :)

    And there's nothing self sustaining about high tech systems.
     
  7. MantaRay
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    MantaRay Junior Member

    .. OK fine, it is not what I thought it was..
     
  8. daiquiri
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    daiquiri Engineering and Design

    Hi NB,

    Regarding the propulsion of the vessel, PAR is right here - a sphere is awfully draggy when moved through water, and even more when moved through the water surface.

    Based on the pics, the diameter of your sphere is around 15 meters. Assuming a half-submerged sphere (as suggested by the position of the engine room) and considering just the pressure and friction drag, you can expect that your vessel will require at least 1000 HP of engine power to move at 9 kts (about the maximum speed you can get with that shape). When you add the wave drag to that figure, you will presumably exceed 1500 HP by a good margin.

    What is the scope of your project?
     
  9. PAR
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    PAR Yacht Designer/Builder

    It'll roll with such an uncomfortable motion, that ball socket gimbles will be needed on everything and lots of sickness bags, made available to guests and crew. It's an absurd set of shapes to employ. I mean no offense with these comments Novice Boaty, but to our eyes, it a bit like saying you've designed an airplane with out wings or a car without wheels. To us, it's obviously a very poor approach, but this isn't to say the concept doesn't suggest possibilities, just that you'll need to gain some understanding of the dynamics and physics involved, with something like this.
     
  10. tomas
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    tomas Senior Member

    My thought is that is it should sit on an oilrig-type platform with submerged hulls (SWATH) for stability with the option to vary the waterline.



    Some design approaches that others have taken:

    http://seaorbiter.com/en/vaisseau/seaorbiter-en-bref/ (Flash animation)

    [​IMG]



    http://www.schwinge.co.uk/index.php?id=7

    [​IMG]
     
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  11. MikeJohns
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    MikeJohns Senior Member

    These fantasy structures are just sci fi if they are intended for unlimited ocean. Before anybody gets excited by form and rendering they would learn a lot reading a few books on ocean engineering particularly wave induced loads and response. It's a well researched and refined knowledge base.

    The Seaorbiter concept with those large horizontal planes will get some horrible loads and induce some severe motion in larger waves. But the stylist is presuming that its nice and calm down there under the surface. It's the same trap people fall into proposing submersible yachts that can pop down just below the surface to ride out a storm.

    A better form is a long cigar that is flipped and the flip ship in vertical mode with the smallest waterplane intersect section is the most sea kindly free floating platform possible in heavy weather. But that doesn't suit the original posters fantasy of sustainability.

    But a nice country estate could be had anywhere in the world for less than the cost of such a platform.

    These sorts of structures are also vulnerable to shipping. Many collisions are avoided by swift manoevering of the priviledged vessel which is underway and has only a few minutes to respond, a structure not under command is usually protected by being anchored and with a large well enforced exclusion zone around it.

    I radioed a large tanker once in the Tasman sea that was on a collision course and I was taking avoiding action. The watchkeeper was alert and had seen us and we decided we'd both hold our courses. I asked what my radar echo was like and he said it was obviously poor otherwise the collision alarm would have gone off . The shortly afterwards he came back and said we made a really good echo but someone had turned the alarm off !
     
  12. tomas
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    tomas Senior Member

    Yes, MikeJohns, reality can not be ignored, hence my first suggestion using the proven oil rig platform (sometimes with SWATH) approach. This approach is also used by http://www.sea-launch.com/ to put satellite payloads into orbit.

    The other designs are grist for the mill, so to speak.
     
  13. PAR
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    PAR Yacht Designer/Builder

    Agreed, these styling exercises are pretty much useless, without a reasonable grasp, of which none of those presented here have much of. The OP's thread hasn't been returned to, so maybe they ran into some reality.
     
  14. Petros
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    Petros Senior Member

    oil rig type plat forms would cost way more than buying some land and building a conventional home. And besides, even the oil rigs sustain heavy damage during storms. If you were inland a bit off a large river you can avoid the heavy weather (and costly ocean front property) and still have access to the ocean for your million dollar yacht and ocean toys. consider how many boats you could own with the savings of building on land instead of a floating navigation hazard.
     

  15. JRD
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    JRD Senior Member

    Come on guys, think of the possibilities!
    Giant concrete football, just add some shipping traffic.
     

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