SOLAS 2009 Lifeboat capacity

Discussion in 'Stability' started by ShinySides, May 4, 2014.

  1. ShinySides
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    ShinySides Junior Member

    I am trying to carry out a SOLAS 2009 damage stability analysis for a university project. The vessel will carry 4005 Pax and 1722 Crew. However we actually have enough lifeboats for 7400 crew. The regulations ask for Lifeboat capacity N_1 and Max number of persons in excess of N_1: N_2.

    I'm not sure which values to use where...
     
  2. Rastapop
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    Rastapop Naval Architect

    The fact that your project is stability analysis doesn't make this (non-stability) question something that should be in the stability sub forum.

    I think it probably should be somewhere else.
     
  3. TANSL
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    TANSL Senior Member

    If I remember correctly, for I am speaking from memory, the number of lifeboats plus liferafts on each side should be sufficient to evacuate all persons on board.
     
  4. ShinySides
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    ShinySides Junior Member

    Ahhh. I did read something about new larger cruise ships being able to evacuate all people on board from one side but didn't realise this was a requirement. I need to look into this. Thanks!
     
  5. ShinySides
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    ShinySides Junior Member

    It is a parameter in the damage stability calculations so Im not sure where else to ask.
     
  6. NavalSArtichoke
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    NavalSArtichoke Senior Member

    I couldn't find the actual regulation in SOLAS, but I believe, based on the description of N2, that is the number of persons carried aboard the vessel for whom NO space is provided in the lifeboats, spare people if you will. I think a reasonable approach would be to assume that:

    N1 = the number of crew + the number of passengers
    and
    N2 = 0

    that way, everyone has a space aboard a lifeboat (no references to the TITANIC, please).

    There may even be some subsequent interpretations issued by IMO regarding this point. It would take some digging, but I would try the imo.org website.
     
  7. TANSL
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    TANSL Senior Member

    Maybe this helps somewhat.
    N2 is the number of persons the ship is permited to carry in excess of N1. Could be >0
    That is, the boat must have express permission to carry this extra number of people.
     

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  8. ShinySides
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    ShinySides Junior Member

    Yes this makes sense, you are right. Do floating doors count? ;)

    I was originally trying to take into account the extra unused lifeboat seats but this seems to increase the required index so is not correct. Thanks for all your responses, I appreciate it.
     
  9. jehardiman
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    jehardiman Senior Member

    Also consider than N (i.e. N_1 and N_2) are a function that drives R, the required sub-division index.

    For a ship built prior to MSC 216, R should have been :R = 1-(1000/(4Ls+N+1500)); where Ls is the subdivision length in meters, and N = boat places+2*excess personnel. So a minimum R would be 0.33 and a maximum would be something just less than 1.0, but never 1.0 or over. Ships built to the current requirement R= 1-(5000/(Ls+2.5N+15225)) So again the minimum R would be 0.32 and the maximum just less than 1.0. What the new rules do however is put more emphasis on people and less on subdivision length.
     

  10. nettersheim
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    nettersheim Consultant

    Sorry to come late on the discussion, but it is important to keep in mind that :

    1) the subdivision of the vessel will be clearly related to the required index R and therefore to the parameters N = N1 + 2. N2

    2) there will be a rather significant difference in the computed value of R when you consider the type of the vessel

    => ferry or cruise vessel
    => cruise will have high N1 and little N2
    => ferry (in general, as an example short international journey) will have high N2 and quite little N1
    => with above assumptions : ferry R > cruise R

    3) in the end the attained subdivision index A will have to be > to the required subdivision index R ( vessel is Solas rules compliant if A > R ) !

    Fran├žois-Xavier
     
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