TRENWICK GROUP INC <TREN> 4TH QTR NET Oper shr profit 18 cts vs loss four cts Oper net profit 1,847,000 vs loss 282,000 Revs 25.9 mln dlrs vs 8,626,000 drs 12 mths Oper shr profit 39 cts vs loss 24 cts Oper net profit 3,262,000 vs loss 1,555,000 revs 67.5 mln vs 27.9 mln dlrs. NOTE: 1986 qtr and year excludes investment gains of 1,541,000 and 1,865,000, respectively, and 1985 qtr and year includes investment gains of 301,000 dlrs and 1,424,000.