Hull Form Selection for Shallow water Craft

Discussion in 'Boat Design' started by wazimjan, Aug 25, 2009.

  1. wazimjan
    Joined: Aug 2009
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    wazimjan New Member

    Hello guys i am new to this forum and i need some help in selection of hull form for a shallow water craft. Can any one guide me how do i approach it is there any specific book or data from where i can get help or any person from design yard/office can guide me. I am listing the some features of the boat

    Draugth=1m (Max)
    Displacement(Deep)=20 Tonnes
    Displacement(Light)=10 Tonnes
    Speed(Max Load)=8-10 kts
    Speed(Light Load)=15 kts

    And i am looking to attach retractable shaft system so that it can be retracted while doing delebrate Broaching
    So according to my opinion the Hull form should be V Type becase of aft shape requiredn for retraction of shaft and this type is also better for shallow water to avaoid Squarting

    Advices Welcome?????????????
  2. Ad Hoc
    Joined: Oct 2008
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    Ad Hoc Naval Architect

    Define 'shallow water'..
  3. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Clearly you're attempting to develop some sort of "special purpose" hull form. Without a full design brief, it would be difficult to advise what shapes to employ. I also disagree in your assumsion of V sections being the best shoal form to prevent squatting. Inverted V possibly.

    In other words a lot more information is necessary about the boat's goals, intended uses, etc. before a reasonable set of answers can be offered.
  4. Willallison
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    Willallison Senior Member

    The most obvious solution - based on the limited info you've given - would be a box keel. This would provide shallow draft, eliminate the need for the complexities of a retractable shaft and (depending on the exact configuration) allow for the speeds you've mentioned. There's quite a bit of info here about box keels - a bit of a search ought to turn up some good threads for you to sift thru. You might also try a google search for the Sea Bright Skiff. They were a variation on the box keel type.
    Can you give us a bit more info? Intended purpose would be a good place to start...also, why the huge difference between light and loaded displacements....
  5. wazimjan
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    wazimjan New Member

    Thanx for help everybody here is a bit more detail if u need anything else be specific what u want?
    the boat will be used in the area where depth is very much variable and worst case is 1m and the purpose is to carry cargo load of around 8 tonnes so there is huge difference in Loaded and unloaded condition and the boat should also be able to operate in Sea State 2 in full load condition and should have a range of 200 Nautical Miles I think that should be enough if u need anything else let me know

  6. peterAustralia
    Joined: Mar 2006
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    peterAustralia Senior Member

    This is a power boat, OK worked that out.

    Now 15m craft, well that ought to be designed with a draught of less than 1m.

    I would say the majority of power craft use a Vee hullform, deep Vee forward, shallow vee or flat aft. How fast do you want to go. What materials do you wish to make it out of.

    I have read a book that deals exclusively with power boat design. Is a good read, can I remember the name, no not really. I do recall that the amount of planing area aft is important. If it is too small then hte craft will not perform well.

    There are no existing designs out there that suit your needs. You must have a sketch or 2?
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