OFFSHORE SUPPLY ASSOCIATION.

Consortium vessels initially retained their owners’ liveries before wider adoption of OSA colours. Some ships outside consortium service kept their original markings. Rosanoski cannot determine whether differences between Loughran and later Brown versions are errors or subsequent modifications. The FOTW O40 flag follows Brown 1995.

Boltentor shows black markings and a black-edged circle, with fleet number 852 below; Marinart confirms the all-black emblem and adds a black funnel top. Burgtor has grey funnels, black tops, a black emblem on a white black-ringed circle, and fleet number 804. Osa Ravensturm appears to have red letters, possibly rust, on the otherwise similar white circle.

OSA was formed in 1966 by D.D.G. Hansa, VTG and Offshore Marine, the last withdrawing in 1973. It had a Singapore subsidiary and joined Ocean S.r.l. in the OSA Marine Services venture. The ownership accounts differ: one gives purchase by O.I.L. in 1988, while Mitchell says Preussag offered the company for sale in 1989.

UK, London; Germany, Hamburg and Bremen.