What type of 4-8 metre hull for speed around 30-35 knots in calm water?

Discussion in 'Boat Design' started by nqb12179, Mar 14, 2014.

  1. nqb12179
    Joined: Jun 2013
    Posts: 13
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Uk

    nqb12179 Junior Member

    I am looking for a hull series which is suit for calm sea.

    Thank you
     
  2. nqb12179
    Joined: Jun 2013
    Posts: 13
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Uk

    nqb12179 Junior Member

    What type of hull is suit for speed around 30-35 knots in calm water?

    How do you know what type of hull is the best and suit for the range of speed?
    1. Displacement
    2. Semi-displacement
    3. Planning
     
  3. tom28571
    Joined: Dec 2001
    Posts: 2,473
    Likes: 115, Points: 63, Legacy Rep: 1728
    Location: Oriental, NC

    tom28571 Senior Member

    You have some wishes that are incompatible. Any small monohull that is going anything near 20mph is planing. What are you planning? Semi displacement speeds depend on length among other things but such a hull is not all suitable for what you are asking.
     
  4. nqb12179
    Joined: Jun 2013
    Posts: 13
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Uk

    nqb12179 Junior Member

    Thank you so much.
    If I reduce the speed of the small ship to around 20knots and length is 8 m.
    Which type of hull and any series will suggest?
     
  5. Mr Efficiency
    Joined: Oct 2010
    Posts: 8,493
    Likes: 473, Points: 83, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    In the absence of further information, you choose a planing hull for that speed range. And needing only to operate on calm water ( not even the wakes of other boats ?) makes it that much easier to satisfy that kind of cruising speed requirement.
     
  6. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 473, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    This thread and the other thread have way too little information, about your desires and needs. There's no such thing as a semi plane boat doing 30 knots, except possibly a Nimitz class aircraft carrier (actually not). Maybe it would be better to better describe what you're looking to do, besides 30 knots in a calm sea. The more information about you needs, the better you can refine the various designs available. Simply put, there's no "ideal" or "best" boat - just ones that fit a difficult to address set of decisions, in regard to several (read many) often conflicting factors.
     
  7. nqb12179
    Joined: Jun 2013
    Posts: 13
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Uk

    nqb12179 Junior Member

    Actually, my desire is to design a motor boat which is for four to five people.
    The range of speed will be more than 20.
    That why I think 8m would be comfortably enough.
     
  8. Mr Efficiency
    Joined: Oct 2010
    Posts: 8,493
    Likes: 473, Points: 83, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    Speed is now down to 20 knots ? I like it, you are flexible ! :D
    I think you need to speak about what the purpose of the boat is, to get any meaningful input from these nice people. :D
     
  9. nqb12179
    Joined: Jun 2013
    Posts: 13
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Uk

    nqb12179 Junior Member

    It is gonna be my family boat where the stability supposes to be sufficient enough and the speed is not too low. We have five people. The hull material will be fibreglass. There is not gonna be a large amount of superstructure weight.
     
  10. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 473, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Save a lot of headache and buy a set of plans in the size and general hull configuration you need, then add the aesthetic and styling touches to make it yours. Based on your questions, you have an awful lot to learn about yacht design and engineering why bother with this, when you can simply make a proven design "yours" for much less effort and the assurance it'll float with the decks facing up on launch day. Lastly, a 24' boat isn't a small project, frankly as a home built, it's a fairly large build. Many hundreds of man hours to complete, not to mention equipment and propulsion systems. It would be much faster to find a used boat, strip it back and add the styling clues and equipment you want. You'll be on the water in a fraction of the time and money, with a custom boat. Simply, a 24' yacht wouldn't be a reasonable first project and it's a lot more work then might seem at the moment. This isn't to say it can't be done, as it has, but it's very rare.
     
  11. SukiSolo
    Joined: Dec 2012
    Posts: 1,270
    Likes: 25, Points: 0, Legacy Rep: 271
    Location: Hampshire UK

    SukiSolo Senior Member

    You could do a lot worse than getting hold of one of these beasts! Depending upon intended use. The f/glass should still be pretty good on a fair few of them despite the age.

    http://www.broads.org.uk/wiki/index...aph&photo=K1_5472&style=RIL&returnpath=notset

    Those hulls make little wash at low speed so ideal on rivers and smooth water but can motor when pushed. Not sure what the top speed is but I have witnessed them chasing planing powerboats on the Thames, no slouch.

    A somewhat period shot of one planing.

    http://www.classicboat.co.uk/buying-and-chartering/bushells/
     
    Last edited: Mar 22, 2014
  12. TANSL
    Joined: Sep 2011
    Posts: 6,061
    Likes: 257, Points: 93, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    Perhaps a multihull, swath, hydrofoil?. Not easy to give advice knowing only the speed.
     
  13. rxcomposite
    Joined: Jan 2005
    Posts: 2,087
    Likes: 216, Points: 63, Legacy Rep: 1110
    Location: Philippines

    rxcomposite Senior Member

    Speed is relative. Perhaps a displacement hull for a VLCC, a semi displacement hull cruise ship, or a kitchen table for planing.
     
    1 person likes this.
  14. NavalSArtichoke
    Joined: Oct 2013
    Posts: 431
    Likes: 8, Points: 0, Legacy Rep: 83
    Location: GulfCoast

    NavalSArtichoke Senior Member

    Not many 30-knot VLCCs, and even cruise ships are cutting back from liner speeds to save on fuel costs. Still, speed is an important factor in setting the other factors in a ship design, particularly length, but it's not the only factor.
     

  15. TANSL
    Joined: Sep 2011
    Posts: 6,061
    Likes: 257, Points: 93, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    I can not imagine that the length of a vessel is a direct function of speed. Of course, for the same displacement, a greater relationship L/B may result in a faster boat but I think that, in general, the length of the boat is deduced by many other parameters.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.