sailboat bows

Discussion in 'Sailboats' started by dman, Sep 19, 2005.

  1. chandler
    Joined: Mar 2004
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    Location: U.s. Maine

    chandler Senior Member

    Thanks Fast Fred, where abouts in Conn. I grew up there,currently in southern Maine
     
  2. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Just for grins. Here are a couple of 33'ers. Very basic, down and dirty stuff. They're actually quite slack bilged. One with 5' freeboard at the bow and one that is 4'.

    The higher freeboard makes the vessel look shorter. More like something in the 20' range. I'd be concerned about windage on such a boat. I don't know that you would gain much in the dryness area either.

    I'd go to the marina or go to some manufacturers websites and get some actual figures off of some boats of that size to see how close or how far you would be from some production boats.

    Oh, these were done with FREE!ship.

    Goodluck
     

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  3. chandler
    Joined: Mar 2004
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    Location: U.s. Maine

    chandler Senior Member

    Thanks learpilot, my design has a more pronounced sheer than those, almost a Maine lobsterboat sheer, I live in Maine. I've been to the boat yards and the manufacturers websites, know something, they all look the same, guess I'll just trust my instincts.
     
  4. LP
    Joined: Jul 2005
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    Location: 26 36.9 N, 82 07.3 W

    LP Flying Boatman

    Chandler,

    New thread, "Lobster"
     
  5. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    When motorsailing , or punching into the waves , a 4 ft freeboard will take water over the bow at 4ft 1 inch of imersion.

    A 5 ft bow will begin to have grean seas after 5ft 1 inch.

    The difference is extreme as much more hull must be immersed to get the slopy seas sweaping aboard.

    Its a foot extra of BOAT that must be immersed.

    FAST FRED
     
  6. James William
    Joined: Apr 2025
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    Location: Florida

    James William New Member

    Great question! What you're referring to is often called a plumb bow (or vertical bow). Unlike traditional raked bows that angle back, a plumb bow drops nearly straight down to the waterline, and yes—increased waterline length is a major reason. But there’s more to it than just that.
    While the plumb bow design might feel unfamiliar and not as intuitive as more sloped bows, it’s primarily about improving performance—especially speed and efficiency. For most recreational sailors, this isn’t as critical, but for racers and performance-oriented cruisers, it's a key design feature.

    If you’re considering a boat with this feature, keep in mind how it might handle in different sea conditions and what your primary sailing goals are!
     
  7. CT249
    Joined: May 2003
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    Location: Sydney Australia

    CT249 Senior Member

    Well….define efficiency and performance! :). Arguably the vertical stem is only more efficient and faster if a boat is measured by LOA, often ignoring bow fittings.

    Increased waterline length, if nothing else changes, normally implicitly increases wetted surface so, all else being equal, often makes a boat slower in flat water or downwind in light airs. A plumb bow can also be a complete PITA for a performance cruiser because it can encourage the anchor chain and anchor to hit the bow when in light winds or handling the anchor. To “solve” that problem many boats now have longer bow fittings - but why fabricate and bolt on a oversized bow roller when you could just rake the bow itself?

    If you take a fixed waterline length and added a raked overhanging bow you inherently increase deck space, forecabin space and often improve anchor handling at fairly low cost, so is that more or less efficient than taking the same fixed waterline length and having a vertical stem?

    It’s interesting that US sailors seem, from what I can see, to be more into perceiving vertical bows as being efficient and cool than Brits and Australians. I wonder whether that’s because many more British and Australian sailors grew up sailing dinghies in a scene where early classes were limited by LOA and therefore had vertical bows. Because we grew up with them, we don’t see them as something new and cool. Meanwhile US and Euro sailors grew up in OD classes that had raked bows (because they are so practical and logical) and therefore see vertical stems as new and cool.

    It’s interesting that when great skiff designers like Julian Bethwaite, Bieker and Morrison design very successful production skiffs and boats like the RS400 and 200 and 29er and 49er, they all dump the vertical bows they use in similar restricted-length classes, and instead go for overhanging bows. Great skiff designers don’t do that to make their boats slower or less efficient. As people from G L Watson to skiff designers have noted, if you simply draw out the lines of a normal fast midships section to their logical and fair conclusions, you inherently end up with an overhanging bow. A vertical bow actually requires distortion of the hull lines from the normal flared midships.
     
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  8. brian eiland
    Joined: Jun 2002
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    brian eiland Senior Member

    The vertical bows on the early NACRA catamarans was all the rage at one time,....and admittedly you could could stuff those bows with less tendency to pitch pole the boat,....BUT you had to make the decks of those bows very slim. On a cruising cat those slim bows produce numerous problems with docking, anchoring etc, etc
     
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