So what went wrong???

Discussion in 'Boat Design' started by ondarvr, May 19, 2014.

  1. Skyak
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    Skyak Senior Member

    I get and accept all that you say above. The question in my head remains about this boat which is intended to circumnavigate. Fuel capacity and use would be significant issues. Deerfoot is the complete opposite -single story, long, efficient....for owners that sail the boat themselves. I just think a three story 90' makes less sense than a 2 story 120'.

    The cost of docking does not seem to be much advantage in this price range. The increased size needed just to carry the extra fuel for the inefficient shape might cover docking increases. I also think of maintenance as proportional to exterior surface area and vessel price though it is often estimated by length.

    The dirty suspicion in my mind is that the shape of this boat was overly influenced by the shape of the builders shop and the interior designer favored by some trophy wife. The silly proportions remind me of the McMansions going up around town -loads of styling detail failing to hide the fact that they are just the maximum rectangular box that will fit the property and regulations. The owner isn't buying a boat. He is buying a townhouse that relocates to ports around the globe. The lives of the crew that get it there don't matter.
     
  2. DavidJ
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    DavidJ Senior Member

  3. jehardiman
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    jehardiman Senior Member

    More on the yacht...

    http://www.charterworld.com/news/tag/northern-marine-8501

    What I find interesting is that in Pufal's blog, the letter he references has a lightship of 110 LT and a full load of 130 LT.

    The article above states that the Northern Marine 85 base design has a "dry" displacement of 315 Klbs (140 LT). Add in the fuel (stated as 5000 gal @ 322 gal/LT so 15.5 LT) and water (1000 gal @ 269.3 gal/LT so 3.7 LT) you get a full load displacement of 159.2 LT. Taking the principle dimensions (78.25*21.5*7.2 = 12,113 cf) and a 0.45-0.5 typical block coefficient for a slack bilge displacement hull, you get an estimated tonnage of 155-173 LT so 160 LT full load is not unreasonable. (Edit to add...God I love it when a plan works out...In Tad's post below from Appendix 6 tonnage at 7.25 foot draft is 158.774 LT.. ;)... )

    If the 110 LT lightship of the blog is correct, and as stated in the newspaper article the the fuel tankage had been increased to 11,000 gal, then the expected load would have been 147.8 LT (holding water the same)....meaning that 12 LT of ballast was available/needed. Not that this amount would bring her back up to the stated "dry" displacement (i.e. 110+12 = 122 which is ~ 130).
     
    Last edited: May 20, 2014
  4. Tad
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    Tad Boat Designer

  5. jehardiman
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    jehardiman Senior Member

    Actually, look at the Righting Arm data table...hummm. Though a weighed weight only off by 5% says a lot about the builder...but what to do with the extra 4 tons...hummm.
     
  6. Rastapop
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    Rastapop Naval Architect

    A longitudinal slip launch can be used for more vessels than any other type of launch (except for options like dry docks, etc).
    Lifting into the water is limited by size and weight.
     
  7. powerabout
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    powerabout Senior Member

    I, ll bet the worlds largest megayachts aren't launched down a slip
    Did I say the boat was designed for a korean ferry operators personal yacht for circumnavigating the icw..lol
     
  8. Rastapop
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    Rastapop Naval Architect

  9. Tad
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    Tad Boat Designer

    Titanic was launched down a slip, the 500' Type 45 British Destroyers were launched down a slip.....

    Titanic-launch-large.jpg
     
  10. NavalSArtichoke
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    NavalSArtichoke Senior Member

    The SS Principessa Jolanda was launched down a slip:

    http://en.wikipedia.org/wiki/SS_Principessa_Jolanda_(1907)

    Whoops!

    Lesson: not all vessels are intrinsically stable at launch. Shipyards used to go to great lengths to do careful weight and c.g. estimates before launch to make sure no problems would occur on the big day. A big black eye for somebody, indeed.
     
  11. powerabout
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    powerabout Senior Member

    a real megayacht as per all the others well known yards dont have slipways, they are left over relic from a bygone era, totally inefficient space wise and to build on
    Show me a yard that has built a new slipway and didnt inherit it fromWWII
    I notice the speed they have to drop that thing in with due to the issues with slipways, case closed.
    https://www.youtube.com/watch?v=afB3MHSScfE
     
  12. djaus
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    djaus Salted Nut!

    Waaaaaay too top heavy. A vessel has no stability while it's on land & I'm guess as she slid down the slip the stern started to float, lifting the hull off it's cradle, over she went.
     
  13. Rastapop
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    Rastapop Naval Architect

    That's too easy. How about a yard that builds yachts? Still easy: Hakvoort built one to accommodate yachts over 200' in 2012.
    http://megayachtnews.com/2014/04/shipyard-spotlight-hakvoort-shipyard/

    The speed isn't something they choose. It's a function of the slope of the slip.

    A stern first launch is preferred over a bow first launch, despite the fact that it slows the launch down (because a slow launch isn't a negative).

    Yards are not thinking "How can I speed this launch up?" If they were they'd just build slips at steeper angles.

    And surely not even you can possibly think that NAs say to themselves after doing the launch calculations "Well at point in time X the boat will want to flip over, so let's just speed up the launch and hope it doesn't happen." This speculation of yours is just utterly absurd.

    Here's Oleg Strashnov launching down a slipway in 2009. It's 183 m (600') - that's longer than Azzam.
    https://www.youtube.com/watch?v=Lp9aE5foOHY


    Fixed that for you.
     
  14. fcfc
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    fcfc Senior Member

    This was for the first designs. Latest ones goes higher :
    http://setsail.com/fpb-78-the-dream-machine-new/

    The FPB 83 was essentially one deck. The latest 78, although shorter, is near tri deck.
     

  15. powerabout
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    powerabout Senior Member

    ya sure that Harkvoort didnt just upgrade their slip that has been there since 1919 when they got the yard or is that slip in a new yard?
     
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