Chapter 3 – Freeboards

  1 The first sentence of paragraph (b)(iv) is replaced by the following:

• "50 per cent of the ship's total capacity of tanks and spaces fitted to contain each type of consumables and stores is allowed for."

  2 After the existing paragraph (b)(iv), a new paragraph (b)(v) is inserted as follows:

• "(v) Ballast water tanks shall normally be considered to be empty and no free surface correction shall be made for them.",

and the existing paragraphs (b)(v) and (b)(vi) are renumbered as (b)(vi) and (b)(vii), accordingly.

  3 The renumbered paragraph (b)(vi) is replaced by the following:

• "(vi) Alternative treatment for free surface may be considered when developing the final condition for application of damage specified in regulation 27(12):

  • (aa) Method 1 (appropriate to virtual corrections). The virtual centre of gravity for the initial condition is determined as follows:

    • I the loading condition shall be developed in accordance with paragraphs (i) to (iv);

    • ii the correction for the free surfaces is added to the vertical centre of gravity;

    • iii one virtual initial condition with all compartments empty is generated on summer load line draught with level trim, using the vertical centre of gravity from the above loading condition; and

    • iv the damage cases will be checked for compliance with the damage stability criteria using the above initial condition.

  • (bb) Method 2 (appropriate to the use of actual free surface moments according to the assumed tank fillings for damage case). The virtual centre of gravity for the initial condition is determined as follows:

    • i the loading condition shall be developed in accordance with paragraphs (i) to (iv);

    • ii one virtual initial condition for each damage case with liquid-filled compartments may be generated on summer load line draught with level trim, using the initial virtual condition with filled compartments generated on summer load line draught with level trim. Using the vertical centre of gravity and free surface correction from the above loading condition separate calculations for each damage case are performed, only the liquid-filled compartments to be damaged are left empty before damage; and

    • iii the damage cases will be checked for compliance with the damage stability criteria using above initial conditions (one initial condition for each damage case)."

  4 A new paragraph (g) is added after the existing paragraph (f), as follows:

• "(g) Compliance with the residual stability criteria specified in paragraphs (a), (c), (d) and (e) above is not required to be demonstrated in service loading conditions using a stability instrument, stability software or other approved method."