Design proposal - help needed

Discussion in 'Boat Design' started by Jon E, Feb 13, 2017.

  1. Jon E
    Joined: Jan 2005
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    Location: Norway

    Jon E Junior Member

    Design proposal - help needed

    I would like to build a "high speed" (15 knot cruise) low power displacement boat who can transport me from A to B - in "safety" (it is relative, i know:)) - in quite rough sea. I do not need liveaboard facilities, other than a comfortable slim cockpit to steer from.

    Is the scetch below a possibility (or something similar), or is the idea plain stupid?

    If possible at all, i am willing to discuss payment for help designing this boat.

    boat_proposal.gif

    • Displacement
    • Self-righting
    • Strong and seaworthy
    • Confortable in rough sea
    • Design weight below 1000 kg?
    • Length: <15 meter
    • Width: 1 meter (waterline) ???
    • Material: Aluminium
    • Cruise: 15 knots?
    • Innboard or outboard?
     
  2. daiquiri
    Joined: May 2004
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    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

  3. Jon E
    Joined: Jan 2005
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    Location: Norway

    Jon E Junior Member

  4. HJS
    Joined: Nov 2008
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    Location: 59 45 51 N 019 02 15 E

    HJS Member

    Semi-planing boat

    It is, in my initial calculations entirely possible to design such a boat. The dimensions you specify indicates that the boat is not a displacement hull. It is a semi-planing boat and must be designed as such. That means it should have a customized transom and not be pointed. Then either the speed or length can be customized to create an optimal boat. But your sketch is a good start.
     
  5. UpOnStands
    Joined: Nov 2015
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    UpOnStands Senior Member

    your first post said high speed. but now its a low power engine?
    high speed at low power suggests a hydrofoil surface skimmer for perfectly flat lakes, certainly not a rough open-water boat with perfect safety.
    your sketch shows a submarine in rough weather, and a very unstable one at that.
    Frankly, total safety at sea and low costs cannot be reconciled. Good enough safety can be achieved a reasonable cost but of course you can never exceed the design (weather) envelop and expect to remain safe. Your decision.
     
  6. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

    Maybe you need to rethink it. Something like this is a proven rough water boat, 15hp outboard, 15 knots. seen here mid way across the Juan de Fuca

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     

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  7. Barry
    Joined: Mar 2002
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    Barry Senior Member

    Looks like this would not be comfortable in a beam sea at 1 meter width and you would not be able to satisfy at least ABYC's guidelines for helm visibility?. I would expect in Norway there would be similar standards
     
  8. Stumble
    Joined: Oct 2008
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    Stumble Senior Member

    You would have to ask a designer, but a very long thin hull with a low power engine may hit the speeds you want, but it would be painfully uncomfortable inside. With no form stability thanks to the extremely narrow hull trying to keep it upright would be a major issue.

    You would almost certainly be forced to move to a prop or Catamaran design instead of a monohull.
     
  9. fredrosse
    Joined: Jan 2005
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    Location: Philadelphia PA

    fredrosse USACE Steam

    29 feet, (8.8 M), 15 Knots, 15 horsepower

    Just for information, here is a steamboat, 29 x 5 (8.8M x 1.5M) Hull, that has demonstrated 15 Knots as a displacement hull, well streamlined compared to the typical wide beam planing hulls. While not exactly what you are looking for, I think this hull form may be close.

    Have a look at 2 minutes into the video. While not a rough water boat in its present configuration, she does get up and go with only 15 horsepower. Click on the link below, and have a look.

    https://www.youtube.com/watch?v=BgzSazdIy5s

    Oberon cuttin some rougher water, look at 20 seconds in:

    https://www.youtube.com/watch?v=6ff9BT3nltU
     
  10. HJS
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    HJS Member

    For the proposed speed and demands for a smooth ride, I would choose a twelve-meter long stabilized monohull, a trimaran.
     
  11. Richard Woods
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    Richard Woods Woods Designs

    But only if you know how it will be docked. Coming alongside and boarding from a pier in a trimaran with small outriggers set low down can be challenging! Pretty much every other boat type allows a crew member to run to the bow to fend off. But then maybe other people are much more skilled sailors than me and always come alongside perfectly

    RW
     
  12. Rurudyne
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    Rurudyne Senior Member

    Look up William Gardner's Tlingit, a comparable low power craft.
     
  13. Rurudyne
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    Rurudyne Senior Member

    Wouldn't swing wings work well with the small amas of a stabalized monohull too?
     
  14. HJS
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    HJS Member

    My choice a trimaran 12,0 x 2,0

    js
     

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  15. UpOnStands
    Joined: Nov 2015
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    UpOnStands Senior Member

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