579 



and until the tank is empty. Provided that the residue then remaining 

 in the tank is subsequently diluted by the addition of a volume of 

 water of not less than 5 per cent of the total volume of the tank, it may 

 be discharged into the sea when all the following conditions are also 

 satisfied : 



(a) the ship is proceeding en route at a speed of at least 7 knots 

 in the case of self-propelled ships or at least 4 knots in the case of 

 ships which are not self-propelled ; 



(b) the discharge is made below the waterline, taking into 

 account the location of the seawater intakes ; and 



(c) the discharge is made at a distance of not less than 12 

 nautical miles from the nearest land and in a depth of water of 

 not less than 25 metres. 



(8) The discharge into the sea of substances in Category B as de- 

 fined in Regulation 3(1) (b) of this Annex or of those provisionally 

 assessed as such, or ballast water, tank washings, or other residues or 

 mixtures containing such substances shall be prohibited except when 

 all the following conditions are satisfied : 



(a) the tank has been washed after unloading with a volume 

 of water of not less than 0.5 per cent of the total volume of the 

 tank, and the resulting residues have been discharged to a recep- 

 tion facility until the tank is empty ; 



(b) the ship is proceeding en route at a speed of at legist 7 knots 

 in the case of self-propelled ships or at least 4 knots in the case 

 of ships which are not self-propelled ; 



(c) the procedures and arrangements for discharge and wash- 

 ings are approved by the Administration. Such procedures and 

 arrangements shall be based upon standards developed by the 

 Organization and shall ensure that the concentration and rate 

 of discharge of the effluent is such that the concentration of the 

 substance in the wake astern of the ship does not exceed 1 part 

 per million; 



(d) the discharge is made below the waterline, taking into ac- 

 count the location of the seawater intakes ; and 



(e)_the discharge is made at a distance of not less than 12 nauti- 

 cal miles from the nearest land and in a depth of water of not less 

 than 25 metres. 



(9) The discharge into the sea of substances in Category C as de- 

 fined in Regulation 3(1) (c) of this Annex or of those provisionally 

 assessed as such, or ballast water, tank washings, or other residues 

 or mixtures containing such substances sliall be prohibited except 

 when all the following conditions are satisfied : 



(a) the ship is proceeding en route at a speed of at least 7 knots 

 in the case of self-propelled ships or at least 4 knots in the case 

 of which are not self-propelled ; 



(b) the procedures and arrangements for discharge are ap- 

 proved by the Administration. Such procedures and arrange- 

 ments shall be based upon standards developed by the Organiza- 

 tion and shall ensure that the concentration and rate of discharge 

 of the effluent is such that the concentration of the substance 

 in the wake astern of the ship does not exceed 1 part per million; 



