Cosag Marine was an offshore company from Aberdeen. They were active in the early 1980's but i am fairly sure they were finished by the middle of the decade
Their address was
Cosag Marine Services
They operated the
Sperus (ex northren Light "Hesperus", built 1939)
Jesmar, later sold to Jesmar Shipping.
All survey vessels, operating in the North Sea, Medi and West Africa.
Mike Davenport and John Lee. After Cosag they went to run small coasters carrying coal.
I dont know what happened after that.