ROWAN <RDC> SEES SUBSTANTIAL LOSSES FOR YEAR Rowan Cos Inc said it expects to incur substantial losses in 1987 despite expected improvement in drilling levels in the Gulf of Mexico and the North Sea. The offshore and onshore drilling company today reported a first quarter loss of 18.6 mln dlrs after a 12.2 mln dlr tax credit, compared with a year-earlier loss of 5,855,000 dlrs after a tax credit of 8,510,000 dlrs. For all of 1986, Rowan lost 42.1 mln dlrs after a 47.6 mln dlr tax credit.