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zone?. Tims, there are free zones in the oceans where discharge of oil may be 

 most indiscriminate. The exceptions to Article III, as amended, require that iC- 

 tanker be proceeding en route (i.e. from one port to another), that the "in- 

 stantaneous rate of discharge of oil content" not exceed CO litres per mile, and 

 that the total quantity discharged on a ballast voyage l)e limited to 1/15,000 of. 

 the total cargo carrying capacity, and also that any discharge must be more 

 than 50 miles from land. This criterion for a limited rate of discharge introduces, 

 a limit that could result in a substantial reduction from present allowable oil 

 discharge levels. 



With respect to ships other than tankers, the amendment provides that the oil' 

 content of the discharge must be less than. 100 parts per 1,000,000 parts of the 

 mixture and the discharge must be made as far as practicable from land. The 

 other provisions concerning instantaneous rate of discharge and "proceeding en 

 route" also apply. 



Returning again to tankers, it should be noted that the amendment with respect 

 to control measures does not apply to the discharge of ballast from a cargo tank 

 wliicli has been freshly cleaned provided that any efihient, if discharged from 

 a stationary tanker into calm water on a clear day, leaves no visible traces on 

 the surface of the water. 



The definitions in Article I of the Convention were amended to take into ac- 

 count the new control measures just described. For example, a definition was 

 provided for "instantaneous rate of discharge of oil content" to mean the rate 

 of discharge of oil in litres per hour at any instant divided by the speed of the 

 ship in knots (nautical miles per liour) at that instant. The term "heavy dieseV 

 oil" was amended by removing the limitation that it be "marine" diesel oil, and 

 the term "oily mixture" was revised to mean a mixture with any content of oil 

 as defined by the Convention. Oil is defined by tlie Convention as crude oil, fuel 

 oil, heavy diesel oil and lubricating oil. The definition of the term "from nearest 

 land" was transferred from Annex A which set out the prohibited zones now 

 made obsolete by new Article III. 



The amendment to Article IV of the existing Convention deleted the exception 

 with regard to the discliarge of residue arising from tlie purification of fuel oil 

 or lubricating oil. 



The amended text of Article V still provides a twelve-month period for ships- 

 to undergo appropriate changes to oil drainage and bilge systems. It should be 

 observed, however, that the present permission for discharge of lubricating oil 

 which has leaked from machinery spaces was eliminated. 



The amendment to Article VII merely provided a consistent use of the term 

 "oil" in accordance witli the definition in Article I. 



With respect to the Oil Record Book, the amendments to Article IX provided 

 for an expanded, yet simplified and precise record to account for all oil received 

 and discharged. It is significant that entries now must be made on a "tank-to- 

 tank" basis. 



The amendment to Article X provides for the prompt reporting of action: 

 taken as a consequence of a Government receiving evidence that a pro\ ision of the- 

 Convention has been violated by a ship of its flag. 



Annex A of the existing Convention setting forth the prohibited zones was^ 

 deleted by the amendment in view of the new provisions concerning discharge in 

 revised Article III. 



The Annex to the 1969 amendment sets forth the revised format for the Oil 

 Record Book. That covers the 1969 amendments to the 1954 Oil Pollution 

 Convention. 



The first of the 1971 amendments to the Convention applies the distance from 

 land criterion for discharges of oil and oily mixture to the area of the Great 

 Barrier Reef as if it were land. The 'Convention amendment reflects the deep 

 concern of the Australian Government that the Reef should be preserved in 

 its natural state free from pollution caused by oil discharges from shiixs. 



The other 1971 amendments relate to the arrangements of vessel tanks and 

 limitations of tank size for new tankers. The theoretical objectives of those- 

 amendments are to place an upper limit on the quantity of oil which can escape* 

 into the sea as a result of collision or other vessel casualty. A proposed Annex C 

 to the Convention wcmld make formidae available for design computations in: 

 connection with tank arrangements and size for tankers built subsequent to the 

 effective date of the amended Convention. Also, certain sliips even now under 

 construction would have to comply with the tank arrangement and size limita- 

 tions within two years after the date the Convention comes into force. That pro- 

 vision would apply to tank vessels presently under construction that will be 



