2 VLCC example

  2.2.1 Each tank capacity and compartment boundaries X_a, X_f, Z_l, Z_u and y are as follows:

  2.2.2 The probability P_s of breaching a compartment from side damage is calculated in accordance with paragraph 8.1 of regulation 23:

From the ratios X_a/L, X_f/L, Z/B_s, Z_l/D_s, Z_u/D_s, Y_l/D_s, and y, the probabilities associated with these subdivision locations are interpolated from the table of probabilities for side damage provided in Paragraph 8.3 of regulation 23.

  2.2.3 The mean outflow for side damage O_MS is calculated in accordance with paragraph 6 of regulation 23.

C₃ = 0.77 for ships having two longitudinal bulkheads inside the cargo tanks extending over the length of the cargo block, and 1.0 for all other ships. In this case, there are two longitudinal bulkheads within the cargo tanks, and C₃ = 0.77.

  2.3.1 Compartment boundaries X_a, X_f, Y_p, Y_s and z are taken as follows:

  2.3.2 The probability P_B of breaching a compartment from bottom damage is calculated in accordance with paragraph 9.1 of regulation 23.

  2.3.3 From the ratios X_a/L, X_f/L, Y_p/B_B, Y_s/ B_B, and z, the probabilities associated with these subdivision locations are interpolated from the table of probabilities for bottom damage provided in paragraph 9.3 of regulation 23.

  2.3.4 Per paragraph 7.3.2 of regulation 23, the cargo level after damage, measured in metres above Z_l, is calculated as follows:

  2.3.5 For the condition with the tidal change tc equal to 0 m, the cargo level after damage hc is 20.153 m. The remaining volume for each cargo tank after damage, in m³, the oil outflow O_B(i) are as follows:

For the condition with tidal change tc equal to -2.5m, the remaining volume for each cargo tank after damage, in m³, and the oil outflow O_B(i) is as follows:

  2.3.6 In accordance with paragraphs 7.1 and 7.2 of regulation 23, the mean outflow from bottom damage is calculated as follows:

  2.3.7 It is recognized that a portion of the oil escaping from a cargo tank may be entrapped by a double bottom tank below, thereby preventing the oil from reaching the sea. In accordance with paragraph 7.4 of regulation 23, C_DB(i) is to be taken as 0.6 when a cargo tank is bounded from below by a non-oil compartment.

  2.3.8 In accordance with paragraph 5.2 of regulation 23, mean outflow values from the 0.0 m and -2.5 m tide conditions are combined in a 70%:30% ratio to obtain the bottom damage mean outflow:

  2.4.1 The non-dimensional mean oil outflow parameter O_M is calculated as follows in accordance with paragraph 5.1 of regulation 23.

  2.4.2 For oil tanker of 5,000 metric tons deadweight and above, the required mean oil outflow parameter is calculated in accordance with paragraph 3.1 of regulation 23.

Since C is equal to 333,200 m³, the required mean oil outflow parameter O_M is as follows.

• Required O_M ≤ 0.012 + (0.003/200,000)(400,000 - 333,200) = 0.0130

  Required O_M, 0.0130 > actual O_M, 0.0095

The vessel is therefore in compliance with the "Accidental oil outflow performance" regulation 23.