Efficient Displacement Hull

Discussion in 'Boat Design' started by ChrissyT, Feb 20, 2011.

  1. ChrissyT
    Joined: Jan 2011
    Posts: 6
    Likes: 1, Points: 0, Legacy Rep: 26
    Location: Plymouth, Devon

    ChrissyT Junior Member

    Hi guys,
    i'm in the process of designing an efficient displacement hull for the use of a passenger ferry to carry 12 people.

    I'm basing the design on the LDL principle and have produced a design on maxsurf and a detailed weight estimate for the craft that passes all the necessary stability criteria etc.

    I'm interested to know what other components will make an efficient displacement hull,i've reduced the beam as much as possible, and created as finer bow as possible,but I'm unsure where to go from here, what hull shapes are most efficient, chine design and position??

    Any help is much a appreciated,
    Thanks guys,

    Here' is some more info,

    My design currently:
    LWL 9.8m
    Beam 3.1m
    Light Ship :3696kg
    Loaded Departure : 4700kg Approx
    Design Speed: 8knots
    Grp Construction
    Coastal, but inshore operation - CAT C with Coding.
    Currently rounded bilge with a soft chine.

    I may stick my design after i have done a bit more work..

    Currently my GZ is 0.732 @ 28 degrees, by my calculation this gives a GM of around 3m for angles of heel under 10 degrees, does this mean my vessel will have excessive stability and be "snappy"? Acceptable given that its for inshore waters?

    I've also constructed a model for the hull and trying to look at how a length will effect stability and resistance.

    Appreciate the advice thanks. ~Info updated..



    Cheers

    Chris
     
    Last edited: Feb 20, 2011
  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    If you are not carrying more than 12 people, you are exempted in the UK from a lot of regulations. Is this to be used in the UK only? What is the area of operation? That will determine a lot of the parameters. I was working in Totnes until recently. We manufactured a 9meter canoe for 12 passengers. There are several in commercial use with a lot of success. With a 2.3HP engine it does 5Kt at half load and 4Kt loaded
     
  3. ChrissyT
    Joined: Jan 2011
    Posts: 6
    Likes: 1, Points: 0, Legacy Rep: 26
    Location: Plymouth, Devon

    ChrissyT Junior Member

    Thanks for the reply, I'm using the ISO 12217 stability and MGN 280 as my criteria.

    Just interested in general design features, such as chine position etc?

    That sounds interesting do you have any more details??

    Chris
     
  4. gonzo
    Joined: Aug 2002
    Posts: 16,790
    Likes: 1,714, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    Before you get to details like chine position, you need to decide of the major characteristics. For example, flat, round or vee bottom. Target speed and sea conditions will also affect the design in a major way. If you already started a design, you should post it so people can critique and comment on it. Otherwise, nobody can tell what you are aiming for. If you want to see and try one of those commercial canoes get in touch with Ian Bowles- teakdecksw@googlemail.com
     
  5. DCockey
    Joined: Oct 2009
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    Location: Midcoast Maine

    DCockey Senior Member

    Gonzo asked some good questions. Here are some others: What waterline length and speed are the targets? Displacement loaded? Construction method - this can be a major factor in determining hull shape? Other targets and limitations?
     

  6. ChrissyT
    Joined: Jan 2011
    Posts: 6
    Likes: 1, Points: 0, Legacy Rep: 26
    Location: Plymouth, Devon

    ChrissyT Junior Member

    Thanks guys,

    Here' is some more info,

    My design currently:
    LWL 9.8m
    Beam 3.1m
    Light Ship :3696kg
    Loaded Departure : 4700kg Approx
    Design Speed: 8knots
    Grp Construction
    Coastal, but inshore operation - CAT C with Coding.
    Currently rounded bilge with a soft chine.

    I may stick my design after i have done a bit more work..

    Currently my GZ is 0.732 @ 28 degrees, by my calculation this gives a GM of around 3m, does this mean my vessel will have excessive stability and be "snappy"?Acceptable give that its operation is inshore waters?

    I've also constructed a model for the hull and trying to look at how a length will effect stability and resistance.

    Appreciate the advice thanks.



    Cheers
     
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