Determine the draft of the hull

Discussion in 'Boat Design' started by prabs, Jun 2, 2021.

  1. prabs
    Joined: Mar 2020
    Posts: 9
    Likes: 0, Points: 1
    Location: India

    prabs Junior Member

    How to determine the draft of a trimaran sailboat? Length: 25 feet, Beam: 8 feet.

    It has 6 stations(longitudinal) in the section view and 3 panels(vertical) in the front view. (Freeship software).

    What value should I input in the draft field?

    What is the ratio between draft to length or draft to beam? What is the optimum? Is there a formula for an optimum draft?

    What is the draft of the ama with respect to the hull?

    Please help me.
  2. bajansailor
    Joined: Oct 2007
    Posts: 1,942
    Likes: 632, Points: 113, Legacy Rep: 37
    Location: Barbados

    bajansailor Marine Surveyor

    Prabs, is this a college assignment that you are working on?
    If so, can you copy out the full text of the assignment here please?

    Re the draft - it depends on what you want from the boat, and what the statement of requirement says, and how much displacement is required..
    You could have deeper draft, and no centreboard, or shallower draft, with a centreboard.

    Re the draft of the ama - again this depends on your displacement. Ideally a racing trimaran would have the amas clear of the water at the load displacement but for a cruising trimaran there will probably be some immersion.
  3. prabs
    Joined: Mar 2020
    Posts: 9
    Likes: 0, Points: 1
    Location: India

    prabs Junior Member

    This is not a college assignment. I would like to understand what draft needs to be specified in the input field of Freeship software along with length(25 ft) and beam(6 ft).

    Number of points in the longitudinal direction: 6 (from stem to stern) (section view)
    Number of points in the vertical direction: 4(3 panels) (Bow/Stern view)
    Length: 25 ft
    Beam: 6 ft
    Draft: ?????

    What is the relationship between draft to length and beam of the hull. Any ideas.

  4. gonzo
    Joined: Aug 2002
    Posts: 15,198
    Likes: 928, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The draft is determined by the hull shape and the weight of the boat. The submerged volume (displacement) is something you need to calculate.
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.