THE Chinese University completed another double in the annual Intervarsity Championships against their University of Hong Kong rivals by winning both the men's coxed eights and women's coxed fours events on the Shing Mun River. It is the third year running that the Chinese University rowers triumphed in both divisions, taking a 4-3 lead in the men's challenge which began in 1987, and a 4-1 lead in the women's race introduced two years after. There were six new faces in the Chinese University men's crew but four months of hard training under coach Luk Chung-leung produced a well-drilled squad who were never in danger of losing. ''We've been preparing for this race since May, but in July we intensified our training and were out on the boat every day,'' said Luk, a member of the 1991 winning crew. ''Our crew were spurred on by the prospect of winning the race for the third straight year and thus earning the challenge trophy for good.'' Luk also attributed their victory to the acquisition of a $100,000 boat from Australia and new scientifically-designed oars, which enabled the crew to post a record time of 13 minutes and 51 seconds for the 4,000 metres event. The Chinese University crew were hard pushed by their University of Hong Kong counterparts in the open waters, but their better co-ordination showed once the race entered the quieter waters of the Shing Mun River. They surged ahead shortly after the half-way mark at the top of the river and packed a stronger finish, pulling away to win by a comfortable two-length margin. Hong Kong national coach Chris Perry said: ''Both teams in this year's race were better than any university crew I've seen in Hong Kong, and both institutions are taking the challenge more seriously than ever before.''