OLJEKSUMENTERNA-OK.
image by Phil Nelson, None
image by Jarig Bakker, None
Brown 1978 and Loughran show a circular rather than oval ring. Phil Nelson’s FOTW drawing follows Stewart 1963.
The funnel follows a black-and-white photograph of the tug Oktan, bought in 1962, renamed Oktan I in 1966 and sold on 21 March 1967. No flag is visible; its applicability is assumed.
The livery changed in 1969, possibly to avoid confusion with Esso. The flag became white with large red OK letters angled slightly per bend sinister. Brown 1978 uses smaller letters set on a diagonal slope rather than angled, while the 1982 and 1995 editions use smaller ordinary letters. Brown 1995 labels this OK Petroleum A/B.