5 The probability of penetrating a cargo oil tank
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Statutory Documents - IMO Publications and Documents - Resolutions - Marine Environment Protection Committee - Resolution MEPC.122(52) - Explanatory Notes on Matters Related to the Accidental Oil Outflow Performance under Regulation 23 of the Revised MARPOL Annex I - (Adopted on 15 October 2004)Amended by Resolution MEPC.146(54) - Annex - Explanatory Notes on Matters Related to the Accidental Oil Outflow Performance under Regulation 23 of the Revised MARPOL Annex I - Part A - Background - 5 The probability of penetrating a cargo oil tank

5 The probability of penetrating a cargo oil tank

  5.1 The probability, PS, of breaching a given cargo oil tank subject to side damage is computed as follows:

PS=(1 - PSf - PSa) (1 - PSu - PSl) (1 - PSy) (5.1)

(1 - PSf - PSa) is the probability that the damage will penetrate into the longitudinal zone defined by transverse planes located at the extreme fore and aft bounds of the tank. (1 - PSu - PSl) is the probability that the damage will penetrate into the vertical zone defined by horizontal planes located at the extreme upper and lower bounds of the tank. (1 - PSy) is the probability that the transverse extent of damage will penetrate into the zone defined by the outboard bulkhead of the tank.

  5.2 Similarly, the probability PB, of breaching a given cargo oil tank subject to bottom damage is computed as follows:

PB=(1 - PBf - PBa) (1 - PPb - PBs) (1 - PBz) (5.2)

(1 - PBf - PBa) is the probability that the damage will penetrate into the longitudinal zone defined by transverse planes located at the extreme fore and aft bounds of the tank. (1 - PBp - PBs) is the probability that the damage will penetrate into the transverse zone defined by vertical planes parallel to centreline, located at the extreme port and starboard most bounds of the tank. (1 - PBz) is the probability that the vertical extent of damage will extend into the zone defined by the bottom of the tank.

  5.3 The extreme boundaries of each compartment are applied when determining the dimensions of the rectilinear block. Although the averaging of sloping boundaries was investigated, it was found that application of the extreme boundaries generally provided more consistent and usually slightly conservative results as compared to the more rigorous procedures discussed in paragraph 10 of regulation 23.

Parent topic: Part A - Background
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