General Purpose Powerboat Hull Design

Discussion in 'Boat Design' started by jdray, Jun 23, 2020.

  1. jdray
    Joined: Jun 2005
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    Location: Portland, Oregon, USA

    jdray Paddle Guy

    Please understand as I ask this question that I am not qualified to design boats. I'm barely qualified to ask intelligent questions about boat designs. I am, by trade and training, a systems analyst, so my approach to things is to break requirements down into service areas, put them in "buckets" as it were, and work to resolve the needs of each particular bucket.

    As far as I can tell, boats (I'll stick to power boats because I understand them better) have a few categories of function, within which are requirements that vary based on the needs of the user:
    • Hull
      • Keeps the water out
      • Keeps the boat and contents buoyant
      • Accommodates passengers and contents
      • Enables the propulsion system to move it through the water at some level of efficiency
    • Propulsion system
      • Transforms energy from a stored state to a kinetic state
      • Pushes hull through the water
      • Operates on some balance of power versus efficiency against the particular hull shape
    • Steering system
      • Steers the boat
      • Possibly integrated with the propulsion system
      • Possibly integrated with the navigation system
    • Communications system
      • ...
    • Hotel functions
      • ...
    You get the idea.

    There's a lot of discussion on this forum about various boat designs, and in every one of them the phrase "it depends" or "everything is a tradeoff" shows up. And I'm not here to argue those truths. I do, however, wonder if there's some sort of "middle ground" hull shape that would meet the needs of a large pool of boaters, and allow builders to have a starting point they can add functionality to as customers needs dictate or boat designers think the market will bear.

    I'm inspired to this concept by things like the CHB-style boats that were built by a number of manufacturers in that group, all based on a standard hull shape and general interior concept; or the E-350 chassis from Ford, on which countless body packages were built to create everything from RVs to utility trucks; or in more modern times, the "skateboard chassis" design for electric cars, on which bodies for a number of uses can be constructed.

    This general purpose powerboat hull design I'm thinking of should be available in a number of sizes; I'm thinking 10, 12, and 15 meters, hopefully designed such that its other dimensions scale parametrically with its length. It should be a V-bottom planing hull. The basic design should be for a single inboard or pod drive propulsion system, though options for twin drives would add flexibility.

    In these size categories, the general use case is either open cruiser (recreational, fishing, etc.) or some sort of power cruiser (weekender, vacationer, liveaboard). In any of those cases, interior volume above the waterline is desired, and beam width should be maintained in the freeboard as much as possible (I don't know what the design style is called, but Pardo's clean lines show it well, with a downward curve near the bow that gets the V of the hull below the waterline quickly and allows the beam to stay wide as far forward as possible; Cranchi does this as well, as do other manufacturers).

    I can think of a huge number of variants that could be based on a hull design like this, from an open runner like the Pardo 38 to a weekender like the Axopar 37XC. Want a flybridge? V-berth? Hard top? Swimdeck? Tender garage? Aft cabin? Mid cabin? You name it, anything should fit inside the hull.

    So here's my list of questions: Is this feasible? Am I way off base in thinking that such a hull design would fit a bunch of different use cases? And does such a design already exist? If so, where do I find it?

    Any commentary you have on my assumptions, whether to correct something or validate it, is welcome. Telling me I'm an idiot for thinking this without explaining where I've said something wrong doesn't help matters, but go ahead if you feel it's necessary.

    Cheers.

    JD
     
  2. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    From the time FRP hulls began to be built using a mold, a hull built with a certain mold has been used countless times to adapt it to many types of boats, passage, fishing , speedboats, provisioning at sea, ... I mean the idea is not only feasible but it is very old and has been carried out many times. Even the same mold can be used to make boats of different lengths and / or different breadths, for monohulls or for catamarans.
     
  3. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Recreational boats are sold mostly as fashion statements. The appeal is not on its practicality. That's left for cheap products, like fishing aluminum jon boats. You are definitely barking up the very wrong tree. The CHB boats you mention would drive any manufacturer into bankruptcy nowadays. The market was OK for that style half a century ago. You need fashion designers and sexy interiors, not a utilitarian vessel that is economic to manufacture. In your list you forgot the most important items: market analysis and economic analysis.
     
  4. jdray
    Joined: Jun 2005
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    Location: Portland, Oregon, USA

    jdray Paddle Guy

    I'm not suggesting the CHB design as an aesthetic, but the idea that a basic hull design can accommodate a number of different use cases, whatever that design is.
     
  5. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    Of course, it can.
     
  6. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    Happens all the time, a basic hull with different upperworks treatments.
     
  7. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Your list is not realistic. The main function of the hull, even though it has to keep the water out, is to appeal to a customer. It has to be fashionable, which means the design will be short lived. It is the reality of consumerism. If it wasn't so, there would be little need for new boats.
     

  8. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    Modern cars look generally ugly to my eye, but it is whatever appeals to the most customers, that guides styling.
     
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