Reverse Bows

Discussion in 'Boat Design' started by quicksail, Mar 30, 2005.

  1. KP Texan
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    KP Texan New Member

    The new DDX has a reverse bow design so I'm sure there is some merit to it.

    The reason I'm posting is to ask about the Ulstein X-Bow design, and I was interested to find that the original designer had actually posted in this very thread! My company is looking into the construction of a 100+ meter Multi Purpose Support Vessel and I have been chosen to head up the engineering side of things. Among other designs, we are considering the Ulstein X-bow and I was curious about the performance of this design. Now that the design has been out for several years, I'm sure that some of you have heard things about these vessels and was looking for some input on its use for our application.

    Thanks so much,

    Wes

    P.S. I'm absolutely blown away by the knowledge on this board and have discovered that I have much to learn!
     
  2. brian eiland
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    brian eiland Senior Member

    Axe Bow

    Hello Wes,
    Try out the 'search button' in doing some research on a subject.

    Also look at "axe bow' for your particular subject matter, and you'll find a few other subject threads.

    This was an interesting addition to one of those subject threads:
    http://www.hiswasymposium.com/pdf/2006/J.%20Gelling.pdf
     
  3. KP Texan
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    KP Texan New Member

    I believe that the Axe Bow and the Ulstein X-Bow are different concepts (I remember reading about the Damen Axe Bow sometime back). After running a search, this thread seemed to have the most information on the X-Bow type vessels so this is where I posed my question. I'll attempt to search for more threads on the X-Bow.

    Thanks so much,

    Wes
     
  4. decatoire
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    decatoire Junior Member

    reverse bow

    olivier decatoire[​IMG]
     
  5. bexman86
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    bexman86 Junior Member

    to me this seems like a case where styling has moved to parts of the boat where it should not be. below the rubrail, styling should take a backseat to practicality!

    and quicksail - in the two pictures you showed... the left one is a yacht with a reverse bow, however the right one is a supply vessel with an x-bow. while the shape of the x-bow (in profile) is similar to a simple reversed bow shape, the idea is different and the x-bow shows increases in hull efficiency as well as improved seakeeping.
     
  6. dskira

    dskira Previous Member

    Reverse bow is a nightmare for the anchor chain. You add a bulbe and you are in real huge trouble. (for a yacht of course)
     
  7. brian eiland
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    brian eiland Senior Member

    I was looking back thru this thread in hopes of finding someone with personal experiences running downwind in big seas with these reverse bows?

    I'm thinking that when surfing real big seas these reverse bows would dig in a bit too much up forward before we even hit the bottom of the wave's slope.
     
  8. Rurudyne
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    Rurudyne Senior Member

    I've read a bit about the x-bow and it seems that part of the magic is that the bow has a lot of reserve buoyancy supporting not much superstructure.

    It isn't really a sleek reverse bow so much as it's a pared back superstructure at/immediately aft of a reasonably bluff bow. Is that correct?
     
  9. brian eiland
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    brian eiland Senior Member

    The x-bow is more of a powerboat type bow,...not the sailing vessel type reverse bow I was looking for comments on
     
  10. brian eiland
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    brian eiland Senior Member

    And a great number of these reverse bow designs don't even include a rubrail at all !!

     
  11. waikikin
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    waikikin Senior Member

    Some great points dskira, aside that you end up with a smaller boat at some greater cost.
    I feel that there's a trend at present for some styling element of this used especially to smallish sailing cats simply as marketing fluff... Aggressive- cutting the sea-blah blah when the reality of traveling with anchorages with wind against current/gnarly wharves etc will see these delicate protuberances for the inconvenience they are... unless the aim is to impress the "ladies" or the other blokes at the bar with the pointyness of the vessel.. once the corners are nocked off all they are is a 50' vessel with a 53' footprint,
    May well be great in a big scale as managed shipping but..
    Jeff
     

  12. Lurch723
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    Lurch723 Junior Member

    I've designed a reverse bow into my 21' tri sailing dinghy. The idea for me has a number of merits, firstly for a given waterline length there is less required structure above the waterline and windage. Secondly I learnt while sailing Hurricanes out at sea they went through a wave and came out the other side having completely ignored it, this is down to a couple of things but a reduced buoyancy at the rear of the hulls helped.

    Whereas racing Darts under heavy load and acceleration they simply went down the mine rather like a skiff (Cherubs etc...). So designing a hull that's more pitch stable in waves by largely ignoring them is a big bonus and I believe the reverse bow aids this along with the correct buoyancy distribution, rapid water shedding blah blah blah.
     
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