The ships of Offshore Marine Ltd were managed by the International Offshore Services (UK) Ltd., London, until 1968. (IOS)
On April 1, 1968 Offshore Marine Ltd. was sold by Hay's Wharf Ltd (London and Rochester Trading ). to the Cunard Steam Ship Co. Ltd. It remained named Offshore Marine.
1968: Foundation of the OSA (Offshore Supply Association (OSA) Ltd, London) as a marketing company. Members were as follows:
Partner organisations were: NVG Nordsee Versorgungsschiffahrt G.m.b.H., Hamburg.
VTG Vereinigte Tanklager und Transportmittel G.m.b.H., Hamburg.
Deutsche Dampfschifffahrts-Gesellschaft "Hansa", Bremen
and Offshore Marine Ltd., Great Yarmouth (Cunard Group).
On December 31, 1972 Offshore Marine Ltd. separated from the OSA.
Interestingly, most folk associate OM with Cunard when, in reality, they were formed by a coasting company and then the Germans.
Hope this helps.