Weight Distribution Question - Sort of...

Discussion in 'Boat Design' started by pede69, Jun 27, 2013.

  1. pede69
    Joined: Jun 2013
    Posts: 11
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    Location: Daytona Beach

    pede69 Junior Member

    Hi Everyone...

    OK.... I have tons of experience building wood stuff so I see no reason to think that my building a boat from scratch would even approach being difficult.

    BUT... I do have one question,

    What are my considerations when it comes to the forward and aft design?, I mean, if I built a hull that is exactly 4 feet high from front to back and I put in, say... a V8, the aft of the boat will be low in the rear and high in the front when in the water.

    How is this overcome in the design of a boat hull?

    Did I explain that correctly?

    Thank you,John
  2. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    John; You can not defeat gravity. Yes the boat will be down by the stern if you load it unevenly. A small,, fast planeing boat is usually "tail heavy". When at rest with no passengers or cargo it will be seen to sink deeper at the stern. The degree of eccentric loading is a matter for informed analysis.

    Displacement boats will be designed such that the loads will be placed more or less evenly about the center of buoyancy of the boat. The boat will then balance reasonably well. Displacement boats are not fast boats but they are more economical to operate.

    Your question is legitimate but it suggests that you will be better advised to buy plans from an acknowledged professional designer. To design the boat yourself is a folly that will surely come back to bite you. The cost of a good set of plans is only a small fraction of the cost of the completed boat.

    Tell us what kind of boat you are considering, what is the primary purpose of the boat? How big will the boat be? Where will it be used? Are you sure you want inboard power? ....etc.
  3. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Welcome to the forum.

    Agreed, though a noble enough ideal, you just don't have sufficient grasp of the basic physics and hydrodynamic fundamentals to engineer the considerable variables involved.

    This isn't meant as a personal dig, just an observation based on your questions. You are quite correct in that, a weight study is one of the very first things you'll perform in the process, just to see how much hull volume and where it needs to be oriented, you'll need for good balance and performance. The locations and arrangement of this volume is dependent on the performance envelop you expect from the boat - each being application specific. There are some rules of thumb, but we'll need much more information about the project and it's goals and even with this, the guidelines these general rules cover will just get you close, not bang on. In slow speed craft, this can be well enough, but high speed craft, you'll want to hone it down pretty tight.

  4. Petros
    Joined: Oct 2007
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    Location: Arlington, WA-USA

    Petros Senior Member

    I would not recommend you design your own boat for your fist build. there are many excellent plans for wood boats by Glen-L and others that do not cost much and will save you lots of trouble, material costs and from making big mistakes.

    You can read up on how the design process works from books and sometimes on this forum if you just want to know how it is done. but as pointed out it is a complex process. It will take you years of spare time study to learn everything you need to know to be successful on your first design/build project before you even start building. with plans you will be enjoying your boat in far less time than if you had to learn how to design a good boat first.
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