Vertical Sailing Craft to circumnavigate Antarctica at 1 knot

Discussion in 'Boat Design' started by rwatson, Apr 14, 2019.

  1. fallguy
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    fallguy Senior Member

    Sort of funny to hear icebergs are no concern.

    Just sayin...
     
  2. JamesG123
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    JamesG123 Senior Member

    Words are hard.
     
  3. Angélique
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    Angélique aka Angel (only by name)

    It's hard for two items only moved by the same systems to get in touch hard.
     
  4. Dejay
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    Dejay Senior Newbie

    What happens when an unstoppable force and an immovable object don't meet?
     
  5. JosephT
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    JosephT Senior Member

    If they stay in the 50's there is usually enough room to maneuver. They'll need to stay well clear of larger icebergs as gale storms sprout on short notice and swirl around. Anxious to see some of their storm video.
     
  6. JamesG123
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    JamesG123 Senior Member

    Get a large styrofoam cooler and a wine bottle, put them into the water on a breezy day and see what happens.

    Iceburgs, even small ones, have tremendous mass and this thing, at the scale depicted, will have a lot of momentum that even a seemingly harmless slow speed will crush itself.
     
  7. Ad Hoc
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    Ad Hoc Naval Architect

    Need to be a bit careful here, especially with terminology. Since you're suggesting a multihull has less stability than a pole, in essence.

    Stability, as in statical stability or seakeeping stability - which are you referring to?

    It is not about the scale per se, it is about the waterplane area to displacement ratio - that's a measure of a vessels restoring force.
     
  8. Angélique
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    Angélique aka Angel (only by name)

    The used terminology in the post #11 answer has to be seen in the context of the post #9 question, which was a comparison with the flipped FLIP in post #7.
     
    Last edited: Apr 15, 2019
  9. Ad Hoc
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    Ad Hoc Naval Architect

    Thanks, I just wanted clarification.

    So addressing this now, as noted, it is all about the waterplane area to displacement ratio. The FLIP is very low indeed, hence the large decoupling of its motions from wave actions.
    But you also have this same effect on large Oil Platforms, as they do the same with thin struts where the buoyancy is in large caissons deeply submerged.
     
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  10. Angélique
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    Angélique aka Angel (only by name)

    Thanks John, that's far more exact wording, hence it explains the principle much better . . :)
     
  11. Angélique
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    Angélique aka Angel (only by name)

    From the above link:
    [​IMG] [​IMG] [​IMG]

    Yes, post #1 also mentioned the spar type oil rigs, saw it's now also used for SeaSteads, will post the link on the appropriate thread and link the post here.
     
    Last edited: Apr 16, 2019
  12. Ad Hoc
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    Ad Hoc Naval Architect

    Taking a few basic assumptions.

    In normal floating mode, the WPA/displacement ratio is roughly 5.3, typical for a heavy for its length vessel, of any kind.
    Yet, when flipped, the ratio drops to around 0.15.

    A Swath is below 2.0....and anything below 1.0 is extreme, like Oil Rigs.

    So when flipped the motions radically change. As natural period of heave is dictated by the waterplane area and its displacement.
     
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  13. rwatson
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    rwatson Senior Member

    "Crews will be surveyed every 2 months using a ship, offshore supply type, which will be permanently assigned to the mission. It will leave the nearest port to join the POLAR POD on its drift course on the 3 oceans."
    POLAR POD - Jean-Louis Etienne - Explorateur https://www.oceanpolaire.org/en/polar-pod/
     
  14. Angélique
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    Angélique aka Angel (only by name)

    One wonders why they don't just take that offshore supply ship to drift around Antarctica by wind and current, and have a sea anchor attached to the bow to keep it upwind during the rough journey.
     
    Last edited: Apr 16, 2019

  15. Angélique
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    Angélique aka Angel (only by name)

    I've posted it on the thread: What do you think of SeaSteading ?post #85
     
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