63.—(1) Subject to the provisions of Regulation 66, before a test for inflammable vapour is carried out with a view to the issue of a naked light certificate for the purposes of Regulation 59 in respect of an oil-tank on board or in a vessel, that oil-tank shall, since oil was last introduced into the tank, be cleaned and ventilated in accordance with paragraph (2) of this Regulation.
(2) The said cleaning and ventilation shall be carried out by the following methods:—
(a)the oil-tank shall be treated in such manner and for such period as will ensure the vaporisation of all volatile oil;
(b)all residual oil and any sludge or other deposit in the oil-tank shall be removed therefrom;
(c)after the oil-tank has been so cleaned—
(i)all covers of manholes and other openings therein shall be removed and it shall be thoroughly ventilated by mechanical or other efficient means with a view to the removal of all oil vapour; and then
(ii)the interior surfaces, if any deposit remains thereon, shall be washed or scraped down.