Trans RINA, Vol 153, Part A1, Intl J Maritime Eng, Jan-Mar 2011


Difficulties arise in the calculations in that the measure of survivability is driven by achieving contributions to the attained index. Therefore, the objective is to arrive at a satisfactory ‘s’ or survivability value when considering a particular damage case with associated delayed flooding, rather than a final equilibrium position after all cross flooding has taken place. The flow rate through the aperture needs to be considered, together with how to address non watertight boundaries that are of sufficient strength to seriously restrict the flow of water. Specified time limits of within 60 seconds


for instantaneous


flooding, or a maximum of 10 minutes to a specified ‘equilibrium’, add to difficulties in arriving at suitable solutions to reflect the regulations, especially when considering multiple compartment damages with several cross flooding scenarios. Questions arise, such as:


At what stage is cross flooding applied as opposed to progressive flooding?, and


Is the software used robust in this application or is an alternative solution better suited?


Figure 6: SCM benefits. 4.2


BENEFITS


For our clients investing in these managers, they can gain the following advantages:


 A right-first-time solution.


 Reduction in errors through missing applicable regulations or being unaware of new regulatory developments.


X=#118  A practical training aid.


 Reduced time from concept to delivery with Lloyd’s Register providing assistance in the design cycle.


 Reduced cost to the designer with fewer changes required in the approval stage.


Figure 5: Example of complex flooding scenario in 1 zone only following starboard damage case.


4. 4.1


STATUTORY COMPUTATIONAL MANAGERS (SCM)


INTRODUCTION


To speed up the stability plan approval process, while implementing a quality system at the same time, Lloyd’s Register has been developing and marketing statutory computational managers (SCMs) to deal quickly and efficiently with damage stability calculations. These have been designed on the NAPA platform which is


the


predominant software used by the industry and Lloyd’s Register alike, particularly for probabilistic stability evaluations. Running detailed models (including escape routes, cross flooding, emergency control


stations, A


Class fire divisions, various openings, and MARPOL oil outflow) through our managers gives us and the client, immediate confidence in the model verification and


The managers are an effective tool, especially when considering the lengthy calculation processes that may be required. Producing managers to encapsulate SOLAS 2009 probabilistic requirements has been a mammoth task. The logic behind the interpretations of the regulations has to be considered in their entirety as opposed to a specific ship or item. Therefore, when dealing with our clients concerning a particular regulation we have also considered the implications holistically to ensure we can maintain a consistent approach into the future for all relevant ship types. Other considerations


are that designers can tackle these


requirements in numerous ways, and we need to have an adaptable platform to cope with these variations. This detailed knowledge further supports us in reviewing submissions made using other tools and methods.


4.3 IMPLEMENTATION


To date, managers have generally been released to deal with ships such as tankers and bulk carriers under version 2009.1.


interpretation process. Advanced options are provided and the full functionality of the advanced NAPA commands remain accessible where required for more detailed review. A substantial reduction in the review process time is achievable.


©2011: The Royal Institution of Naval Architects


A-5


R54.1 R54 R54.5 R54.4 R54.2 R53P R64.2 R53 R74.3 CAS5 R611 R53S T4 R612 R63.2 R52P 52 R611 R62P R52S R612 T4 R62 R711 T89 T88 R81 R83 T2 T25 T3 R611 R711 R612 R61 R81 R60 R62S T41 R71 R83.1 R63.1 R71 R73.2 R73.1 R84 R63 R711 CAS4 R74.2 R54.6 R54.7 R64 R64.1


R54.3


R64.3 R74


R84.1


R84


R71 T41 T2 T25 T3 R60 R711


T81 R70C T68 T46 T54 R701 R70S R801 T51 T76 T58 T49 T52 T56 R T50 T85 T77 T48 T47 T94 T87 T45 T82 T62 T53 R70P


R81


R73.1 R74


R70P T53 R71 R70C T45 T82 T68 T46 T54 R70S R711


CAS5 FZ2 R74.3


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