114 
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 ; 
(0) 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. 
(2) The discharge into the sea of substances in Category B as defined 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 sub- 
stances shall 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 ships which are 
not self-propelled ; 
(0) the procedures and arrangements for discharge are approved by the 
Administration. Such procedures and arrangements shall be based upon 
standards developed by the Organization and shall ensure that the concen- 
tration 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 ; 
(c) the maximum quantity of cargo discharged from each tank and its 
associated piping system does not exceed the maximum quantity approved 
in accordance with the procedures referred to in sub-paragraph (b) of this 
paragraph, which shall in no case exceed the greater of 1 cubic metre of 
1/3,000 of the tank capacity in cubic metres; 
(@) the discharge is made below the waterline, taking into account the 
location of the sea water intakes; and 
(e) 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. 
(3) The discharge into the sea of substances in Category C as defined in Reg- 
ulation 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 sub- 
stances shall 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 ships which 
are not self-propelled ; 
(b) the procedures and arrangements for discharge are approved by the 
Administration. Such procedures and arrangements shall be based upon 
standards developed by the Organization and shall ensure that the concen- 
tration 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 10 parts per 
million ; 
(c) the maximum quantity of cargo discharged from each tank and its 
associated piping system does not exceed the maximum quantity approved in 
accordance with the procedures referred to in sub-paragraph (b) of this 
paragraph, which shall in no case exceed the greater of 3 cubic metres or 
1/1000 of the tank capacity in cubic metres; 
(b) the discharge is made below the waterline, taking into account the 
location of the seat water intakes; and 
(ec) 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. 
(4) The discharge into the sea of substances in Category D as defined in Regu- 
lation 3(1)(d) of this Annex, or those provisionally assessed ns 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 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) such mixtures are of a concentration not greater than one part of the 
substance in ten parts of water; and 
(c) the discharge is made at a distance of not less than 12 nautical miles 
from the nearest land. 
