More excellent input, thank guys.
I checked out Hector Gannet and little data to be found about her. It does appear that the incident happened in 1968 which places it around the time of the Cunard acquisition. In the absence of anymore detail regarding dates and Don's comment perhaps this vessel didn't actually form part of the acquired fleet.
I've also looked into the sale of OM to Zapata and whilst google turns-up a press release, annoyingly it is undated but there is one clue, it does go on to say that at the time there where 24 vessels within OM. I will try and work through what I information I aleady have and see if I can piece it together. In owendvdsn earlier response I tend to agree that it was either 1980 or 1981.
Last edited by cap0557; 17th August 2011 at 08:22..