Both pair crews, Eric Murray and Hamish Bond, and Genevieve Behrent and Rebecca Scown, won well to advance. The men, unbeaten in seven years, were 3s ahead of Serbia in their heat, recording 6:32.050 to move into the semifinals.
The latter stages could yet be interesting, with the British No 1 crew winning their heat in near-identical time. Second New Zealand pair Axel Dickinson and Drikus Conradie were third in their heat, in 6:38.460 to also make the semifinals.
Behrent and Scown clocked 7:07.970 to cross almost 3s ahead of the Romanian crew to move directly into the A final.
There were other heat wins for the lightweight men's four of James Lassche, Matt Dunham, Alistair Bond and James Hunter, men's double of Chris Harris and Robbie Manson, both of whom are into the semifinals; lightweight women's single Zoe McBride won her heat in the non-Olympic discipline but there were problems for double scullers Zoe Stevenson and Eve Macfarlane.
Having finished last in their final at the Lucerne World Cup at the end of last month, the defending world champions trailed in last in their heat today in 7:11.440, 12s slower than heat winners Australia, and have a repechage late tonight.