Lifeboat

Discussion in 'Boat Design' started by PAUL XAVIER, Jan 6, 2016.

  1. PAUL XAVIER
    Joined: Apr 2014
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    PAUL XAVIER Junior Member

    I wonder what is the material used for construction of a lifeboat.
    What is its density?
    For a closed dumb lifeboat (dimension 10x3.5x3.5) constructed using this material, what will be the approximate lightship displacement?
     
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Your questions are too broad in scope to answer properly. Several materials can and have been used in lifeboat construction, though 'glass is quite common now. Are you a student and is this a program presented problem?
     
  3. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    GRP of a sufficient thickness will roughly be 3 lbs per SQ foot , about 1/2 inch thick.

    Decide on the surface area and multiply.

    Then add fuel /water tanks , engine , batteries and radios.
     
  4. TANSL
    Joined: Sep 2011
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    TANSL Senior Member

    "3 lbs per sq foot, about 1/2 inch thick" seems a fairly accurate weight for the panels, if that figure takes into account resin, but also you should take into account the weight of the reinforcements (frames, longitudinal girders, deck beams, deck girders,....)
    For the lightship weight you need to "add fuel / water tanks, engine, batteries and radios," and many other weights (engine, anchor, deck gear, steering gear, shaft, propeller ...? )
     
  5. PAUL XAVIER
    Joined: Apr 2014
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    Location: chennai

    PAUL XAVIER Junior Member

    Thank you for your replies
    @PAR yes I am a student and its for research purposes,actually nothing related with lifeboat.
    I just want to include an enclosed body to deal with oil spillage issues.

    @TANSL,@FAST FRED There is no engine,radio etc although there will be internal strengthening members.

    I have made a successful small prototype using plastic and glue.But that can never be taken to ocean environment.So I just want to add up details about the approximate lightship and dimensions of this equipment in the thesis.

    And in t/m3 unit I got GRP's density around 1.5.

    I really appreciate your replies :)
     
  6. TANSL
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    TANSL Senior Member

    1.5 t / m3 seems an extremely high figure for the GRP.
    I am sure that you will have to add some other items on the lightship weight, besides hull and internal strengthening members. If not, we are not talking of the lightweight but something else.
     
  7. Heimfried
    Joined: Apr 2015
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    Heimfried Senior Member

    According to my sources 1.5 t/m³ is not high. Resin without fibre is about 1.2 t/m³, glass fibre about 2.5 t/m³.

    Depending on the ratio resin/glass the density should bee between this values. Mostly it is said to be 1.8 t/m³.
     
  8. TANSL
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    TANSL Senior Member

    Heimfried, maybe you are right. The actual data that I have is that a panel, with 33% by weight of fiber, 13.8 mm thick, weighs 6.65 kg / m2 without resin.
     

  9. sharpii2
    Joined: May 2004
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    sharpii2 Senior Member

    My guess is that the completed boat, without passengers, fuel and other stores will weigh in at about 4.0 mt. Fully loaded, it will weigh two to three times as much, depending on its passenger compliment and expected range.
     
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