Lightship with segregated ballast condition

Discussion in 'Stability' started by athvas, Aug 25, 2014.

  1. athvas
    Joined: Feb 2013
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    Location: india

    athvas Senior Member

    Hi

    Could anyone tell me the loading of Lightship with segregated ballast only.. Is it the condition with lightship + all the ballast tanks filled or any other meaning? what is meant by segregated ballast ?
     
  2. NavalSArtichoke
    Joined: Oct 2013
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    Location: GulfCoast

    NavalSArtichoke Senior Member

    Oil tankers are no longer permitted to put ballast water in cargo tanks. Special, dedicated tanks for ballast water are constructed into the hull of modern tankers for use when the vessel is carrying no cargo or only a partial cargo, so that trim can be maintained or the propeller or rudder be kept immersed for efficient operation.

    http://en.wikipedia.org/wiki/Architecture_of_the_oil_tanker

    Most single hull tankers have been phased out under international conventions like MARPOL or other national regulations like the US OPA 90. In newer double-hull oil tankers, the space between the outer shell and the cargo tanks is usually used for ballast.
     
  3. athvas
    Joined: Feb 2013
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    Location: india

    athvas Senior Member

    Yes as you said i have shown the loading condition with lightship + all the ballast tanks filled 100% capacity (only ballast tanks intented to carry ballast water). but the class has commented that the ballasts are not segregated.
     
  4. NavalSArtichoke
    Joined: Oct 2013
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    Location: GulfCoast

    NavalSArtichoke Senior Member

    Well, I don't know anything about your vessel, but I suspect class does.

    I believe there may be some older tankers still sailing which do not have segregated ballast tanks. Under the MARPOL convention, all tankers of 20,000 DWT and above without segregated ballast tanks should have been phased out by 2005. Smaller tankers, those between 5000 and 20,000 DWT without segregated ballast, should have been phased out by 2010. It's possible your vessel could be under 5000 DWT. IMO has given flag state administrations some discretion in phasing out smaller tankers in the 5000-20,000 DWT range, but the final phase out of these vessels must occur by 2015.

    You should find out more from the class society about the implications of this for your vessel owner. In other words, you have more serious issues to deal with than just putting together a loading condition.
     

  5. Dr34m3r
    Joined: Mar 2012
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    Location: Finland

    Dr34m3r Senior Member

    Segregated ballast tanks. These are tanks which must be provided on board crude oil tankers after the MARPOL 1973/1978 Convention entered into force in 1983. Cargo oil and ballast must be segregated to prevent pollution. Segregated ballast is ballast water that is introduced into a tank which is completely separated from the cargo oil and oil fuel system and which is permanently allocated to the carriage of ballast or to the carriage of ballast or cargoes other than oil or noxious liquid substances.
     
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