drawing midship section of catamaran

Discussion in 'Boat Design' started by shrijeet mishra, Apr 1, 2020.

  1. TANSL
    Joined: Sep 2011
    Posts: 7,369
    Likes: 699, Points: 123, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    Always so perfectionist and so kind. It looks like the OP is smarter than you, or less pretentious, and has figured out what that meant. So yeah, I hope that was able to help him.
     
  2. Ad Hoc
    Joined: Oct 2008
    Posts: 7,773
    Likes: 1,678, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Still don't see defining what "stands of a ship" means.... :eek:

    Yes, such wonderful advice you gave:

    you are really magnanimous... :)
     
  3. TANSL
    Joined: Sep 2011
    Posts: 7,369
    Likes: 699, Points: 123, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    Thank you, dear Ad Hoc (not admired), for your always funny responses. Your sense of humor (which doesn't exist) is what I like most about you. Thank you for your generosity and humility that is an example for everyone.:D
     
  4. gonzo
    Joined: Aug 2002
    Posts: 16,790
    Likes: 1,714, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    I was only focusing on the ease of construction and design of a chine hull over a rounded one. If you look at the first hull section image Ad Hoc posted in #12, it shows the structure is simpler. Since this is homework, if they give you the opportunity to choose, the simplest structure makes sense.
     
  5. TANSL
    Joined: Sep 2011
    Posts: 7,369
    Likes: 699, Points: 123, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    Define.. "magnanimous":D
     
    shrijeet mishra likes this.
  6. shrijeet mishra
    Joined: Feb 2020
    Posts: 32
    Likes: 1, Points: 8
    Location: india

    shrijeet mishra Junior Member

    no sir not a homework its my project work so i chose such as per NPL.
     
  7. gonzo
    Joined: Aug 2002
    Posts: 16,790
    Likes: 1,714, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    If this is a project for yourself or a client, you need to rethink the design. Fast catamarans have less submerged volume and more freeboard. By their nature, they have to be light. Is the Chapter 8 you posted originally part of the Statement of Requirements (SOR)?
     
  8. TANSL
    Joined: Sep 2011
    Posts: 7,369
    Likes: 699, Points: 123, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    Freeboard has nothing to do with boat's speed. You need to have clear concepts.

    A first outline for what it could be to start defining your main section would be something similar to that of the attached plan. I insist that in a first draft that will only serve to cross out, correct and add elements, according to the structure that you have in mind.
     

    Attached Files:

    Last edited: Apr 4, 2020
  9. Suhas
    Joined: Apr 2020
    Posts: 5
    Likes: 1, Points: 3
    Location: Kochi, India

    Suhas Junior Member

    Hi Sreejith,
    I work with GRP Cataraman construction in Kerala, India. I understand this is for your college project but from a more practical aspect, you aft end sections are very steep towards the keel area. It would be very difficult to create a mould of this dimensions and do subsequent layering on them. I suggest you go with round bilge sections or make chined hulls with smaller deadrise angles.
    From design persepective, once you have fixed your scantling calculations as per class rules. Start with a large centreline girder along the CL of Hull and space your hull longitudinals with respect to your CL Girder. Make note to provide additional lamination thickness over Keel, Bottom and Sides as per your scanting calculations. If I remember right, as per IRS HSLC Rules, Bottom thickness extends 150mm above your scantling draft.
    For FRP construction, stiffeners are generally air cored top hats as indicated in the rule book. Bonding with hull depends on your stiffener tabbing length, good practise to provide a 50mm tabbing on first layer and 15mm on subsequent ones.
    PS: AutoCAD drafting is very easy once you are familiar with all the commands.
    Good luck with your project.
     
    shrijeet mishra likes this.
  10. Ad Hoc
    Joined: Oct 2008
    Posts: 7,773
    Likes: 1,678, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    Ok..one more try:

    Please explain what "stands of a ship" means....
     
  11. TANSL
    Joined: Sep 2011
    Posts: 7,369
    Likes: 699, Points: 123, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    Think a little, man !, a little effort that you can get it. A little tip, use your head, not your feet.:D
     
  12. Ad Hoc
    Joined: Oct 2008
    Posts: 7,773
    Likes: 1,678, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    So.... TANSL replied to a questions with a statement:

    I have now asked 3 times, since this is an educational forum, what does.....the stands of a ship.... mean.

    And the replies thus far are:

    and
    and
    and
    So, that's a no then. You cannot define the phrase....the stands of a ship.... that you used in a reply.

    But then you imply:

    How do you know this,???... because you do not know what it means.
    If you did, you would have replied with the definition of the phrase, to educate those that have never heard of this before, rather than waste bandwidth with utter nonsense, as is your usual MO.
     
  13. shrijeet mishra
    Joined: Feb 2020
    Posts: 32
    Likes: 1, Points: 8
    Location: india

    shrijeet mishra Junior Member

    no that chapter is part of whole project. this chapter need to do the midship of vessel.
     
  14. shrijeet mishra
    Joined: Feb 2020
    Posts: 32
    Likes: 1, Points: 8
    Location: india

    shrijeet mishra Junior Member

    thank you so much sir.
    yes sir its the project i hope u must knowing of CUSAT ship tech.
    i have round bilge hull sir as per NPL my offset i took deriving from their modelled offset.
    it would be nice if u have look over the excel as you are already working on these kind of vessels.

    drawing on autocad is easier but yeah those commands. ill try by time ill start drawing on chart paper.
     

  15. shrijeet mishra
    Joined: Feb 2020
    Posts: 32
    Likes: 1, Points: 8
    Location: india

    shrijeet mishra Junior Member

    one more doubt sir
    while defing the thickness of web of attached plate span basically the scantling of hat stiffeners and the structure overall
    we can choose the thickness as per our requirement to satisfy the section modulus right?
    is there any hard and fast rule stating no it must 9, 9 , 11 or 7, 7 , 9
    something like this?!

    ive placed such values and got satisfactory section modulus so it will be good i hope ?!
     
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.