6 The
requirements of regulations 29, 31 and 32 of this Annex shall not apply
to oil tankers of less than 150 gross tonnage, for which the control
of discharge of oil under this regulation shall be effected by the
retention of oil on board with subsequent discharge of all contaminated
washings to reception facilities. The total quantity of oil and water
used for washing and returned to a storage tank shall be discharged
to reception facilities unless adequate arrangements are made to ensure
that any effluent which is allowed to be discharged into the sea is
effectively monitored to ensure that the provisions of this regulation
are complied with.