284 



fc) Where the damage between adjacent transverse watertight bulkheads is 

 envisaged as specified in sub-paragraph (l)(o) of this Regulation, no main 

 transverse bulkhead or a transverse bulkhead bounding side tanks or double 

 bottom tanks shall be assumed damaged, unless : 



(i) the spacing of the adjacent bulkheads is less than the longitudinal extent 

 of assumed damage specified in Regulation 22(a) (i) of this Annex: or 



(ii) there is a step or a recess in a transverse bulkhead of more than 3.05 

 metres in length, located within the extent of i^enetration of assumed damage : 

 the step formed by the after peak bulkhead and after peak tank top shall not 

 be regarded as a step for the purpose of this Regulation. 



(d) If pipes, ducts or tunnels are situated within the assumed extent of dam- 

 age, .arrangements shall be made so that progressive flooding cannot thereby 

 extend to compartments other than those assumed to be floodable for each case of 

 damage. 



(3) Oil tankers shall be regarded as complying with the damage stability 

 criteria if the following requirements are met : 



(a) The final waterline taking into account sinkage, heel and trim shall 

 be below the lower edge of any opening through which progressive flooding may 

 take place. Such openings shall include air pipes and those which are closed 

 by means of weathertight doors or hatch covers, and may exclude those openings 

 closed by means of watertight manhole covers and flush scuttles, smal water- 

 tight cargo tank hatch covers which maintain the high integrity of the deck, 

 remotely operated watertight sliding doors, and side scuttles of the non-opening 

 type. 



(b) In the final stage of flooding, the angle of heel due to unsymmetrical flood- 

 ing shall not exceed 25 degrees, provided that this angle may be increased up to 

 30 degrees if no deck edge immersion occurs. 



(c) The stability in the final stage of flooding shall be investigated and may 

 be regarded as sufficient if the righting lever curve has at least a range of 20 

 degrees beyond the position of equilibrium in association with a maximum 

 residual righting lever of at least 0.1 metre. The Administration shall give con- 

 sideration to the potential hazard presented by protected or unprotecte<l open- 

 ings which may become temporarily immersed within the range of residual 

 stability. 



(d) The Administration shall be satisfied that the stability is suflicient dur- 

 ing intermediate stages of flooding. 



(4) The requirements of paragraph (1) of this Regulation shall be confirmed 

 by calculations which t.iike into consideration the design charactteristics of the 

 ship, the arrangements, configuration and contents of the damaged compart- 

 ments as well as distribution, si>ecific gravities and the free surface effect of 

 liquids. The calculations sUall be based on the following : 



(a) Account shall be taken of any empty or partially filled tank, the specific 

 gravity of cargoes carried, as well as any outflow of liquids from damaged 

 compartments." 



(b) The permeabilities are assumed as follows : 



Spaces Permeahility 



Appropriated to stores 0.60 



Occupied by accommodation 0.95 



Occupied by machinery 0.85 



Voids 0.95 



Intended for consumable liquids or 0.95* 



Intended for other liquids 9 to 0. 95** 



•Whichever results in the more severe requirements. 



♦♦The permeability of partially filled compartments shall be consistent with the amount 

 of liquid carried. 



(c) Tlie buoyancy of any superstructure directly above the side damage shall 

 be disregarded. The unflooded parts of superstructures beyond the extent of 

 damage, however, may be taken into consideration provided that they are sepa- 

 rated from the damaged space by watertight bulkheads and the requirements of 

 sub-paragraph (3) (a) of this Regulation in respect of these intact spaces are 

 complied with. Hinged watertight doors may be acceptable in watertight bulk- 

 heads in the superstructure. 



" Further study should be carried out to assess the effect of outflow of liquids from 

 damaged compartments. 



