calculations for bow types

Discussion in 'Boat Design' started by jake wilson, Dec 1, 2020.

  1. jake wilson
    Joined: Oct 2020
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    jake wilson Junior Member

    Hello ... I'm designing a model of motor yacht. I have made a model out of the dimensions and checked it displacement as well. Now I'm planning to make different bow forms to suit the model. So I would like to know if there are any particular calculation for bulbows bow. I'm planning to model axe bow, flared bow and x bow.
  2. DCockey
    Joined: Oct 2009
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    DCockey Senior Member

    Calculations of what?
  3. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    Bulbous bows are designed for a narrow speed range. They are usually not used on yachts because the speed changes a lot. Maybe yachts that travel very long distances (crossing oceans) on a regular basis could be a good candidates. What are you calculating?
    Ilan Voyager and Olav like this.
  4. Olav
    Joined: Dec 2003
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    Olav naval architect

    jake wilson,

    please see attached PDF for some design guidelines for bulbous bows. For sure not the ultimate stuff on that topic but it might get you somewhere in the right ballpark though.

    Also I second gonzo's statement: Bulbs can backfire easily, not only when used outside their intended speed range, but also with changing draught and trim of the vessel.

    Attached Files:

  5. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    I always thought that the bow bulb was designed to be most effective at a certain displacement (not speed) of the ship. You always learn something new.
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