Late Steve Job's yacht launched

Discussion in 'All Things Boats & Boating' started by liki, Oct 29, 2012.

  1. Tackwise
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    Tackwise Member

    [​IMG]
    I am afraid she has a visitor with not the same exquisite taste!!!
    Its destroying her lines!!
    Away with you....
     
  2. daiquiri
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    daiquiri Engineering and Design

  3. viking north
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    viking north VINLAND

    These so called modern designs remind me of the early 1900 commuter styles. I have often questioned the seaworthyness of what I would term constant displacement bows. I.E. the bows have no flair thus no increase in displacement (boyancy) as it pierces a wave. Wouldn't it tend to plow into rather than rise when encountering a sea. Certainly would not be my choice of vessel for open ocean crossings.
     
  4. watchkeeper

    watchkeeper Previous Member

    I think the SJ/PS design is to yacht design what 1960's England's council tower flats were to UK architecture a failed experimental phase that the sooner corrected the better for yacht designing
     
  5. DCockey
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    DCockey Senior Member

    The displaced volume of the a slab-sided bow will increase as the bow encounters a wave. More the bow will be submerged so the displaced volume increases. The rate of increase of displacement as the bow is submerged will be less than that of a flared bow with the same static waterplane shape.
     
  6. michael pierzga
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    michael pierzga Senior Member

    A needle nose will push thru the waves and use less energy for both wave penetration and from hobby horsing.

    To work , a needle nose boat must be very light forward. That's the reason the anchor and chains are housed all the way aft in the Galley.

    A box shaped boat will have the longest waterline .

    The boat seems to want to be ECO friendly or GREEN.

    The exterior is definitely goofy looking and unusable...perhaps inside the boat are some interesting ECO friendly systems.
     
  7. viking north
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    viking north VINLAND

    Am I correct in assuming for a given size boat (bow flaring verses this style ) this style bow is more subject to green water over the fore deck with the resultant damage and danger that entails.
     
  8. michael pierzga
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    michael pierzga Senior Member

    As long as you understand its sea keeping charecteristics you can create defense .

    The conceprt of the axe bow is to reduce verticle acceleration , energy use and improve crew comfort . This is why North sea supply craft use it.

    Every plumb stem, needle nose, Ive been on has been wet.

    Not a good choice for yachts in my opinion.
     

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  9. viking north
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    viking north VINLAND

    Those bow superstructures make for some strange looking craft. I am attracted to the upper middle design -- Looks like it is certainly built to compensate for boarding seas. Speaking of sea's i best get myself out to the shop and work on my own build's bow section. ---:D
     
  10. BPL
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    BPL Senior Member

    I disagree. The strong contrast makes both more beautiful to me.
     
  11. Tad
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    Tad Boat Designer

  12. High Life
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    High Life Junior Member

    Thanks for the interview. I would like to see how Venus works from the inside. From the outside it's not my favorite of his work.
     
  13. Stephen Ditmore
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    Stephen Ditmore Senior Member

    The problem with this analysis is that deck & superstructure weight, including weight in the ends, drive VCG up. Ballast is then needed to bring VCG down, so deck & superstructure weight drive displacement. For this reason I suggest one ought to compare two vessels with the same deck area, superstructure, and freeboard, not two vessels with the same waterplane.

    A lighter displacement vessel (lower ratio of displacement to waterline length) with less weight in the ends has a lower mass gyradius. A vessel with an extended waterline has a higher longitudinal waterplane moment of inertia and therefore more longitudinal stability.

    Then consider the point at which the foredeck is immersed. A vertical or aft-raked bow results in volume being immersed sooner going into a wave relative to the forward end of the flat weather deck. For more on this see http://www.surfski.info/latest-news/item/1281-point-65-bourbon-orca-design-notes.html

    If I were designing a boat with a plumb or reverse bow I'd be careful about letting LCB (which corresponds to LCG) get too far ahead of LCF (center of waterplane). On a multihull I might even put LCF forward of LCB. This type of bow will pop up if the lever between the buoyancy forward and LCG is sufficient. Before I'd be entirely comfortable with the hulls in the photos supplied by Michael, or Steve Jobs' boat, I'd have to study the curves of form.

    For any given waterline length and beam a boat with a higher waterplane area coefficient (fuller ends in planform at the waterline) will have a higher longitudinal waterplane moment of inertia, and therefore more longitudinal stability, than one with a lower waterplane area coefficient. For any given Cp a boat with a high waterplane area coefficient will have rocker with more curvature concentrated near the middle, which is what you see in recent catamaran design (in the America's Cup catamarans, for example).
     
  14. watchkeeper

    watchkeeper Previous Member

    Thanks Stephen, interesting video. The Dophin crew vessel comparison is like watching a displacement hull compare with a SWATH sailing in high sea state conditions
     

  15. High Life
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    High Life Junior Member

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