Fiona Bourke missed out in a desperate race for the line in the single scull.
Bourke, who has replaced last year's world champion Emma Twigg in the single due to Twigg taking a year out, was squeezed into fourth spot in her quarter-final, won by Belarus. Only the first three advanced.
Belarus won the race while Bourke and scullers from Ireland and Zimbabwe were covered by .740s as they dashed for the line. One had to miss out and it was Bourke.
World champions Mahe Drysdale, Eric Murray and Hamish Bond, and Julia Edward and Sophie Mackenzie all moved into semifinals in the men' single scull and coxless pair, and lightweight double scull respectively. The men won their quarter-finals, Edward and Mackenzie were second.
The women's quad of Georgia Perry, Sarah Gray, Lucy Spoors and Erin-Monique O'Brien also moved into their final after finishing second in their repechage, clocking 6:30.200 to squeak through by just .160s ahead of third finishers China.
"We had a fast start in the choppy water and then the other crews started to pull back a bit of us, then it was just a really tight wind to the finish line," O'Brien said.
"We just wanted to stay in control, stay steady and keep breathing. When it comes to the final we've got to really shoot for that first place and it's anyone's game in the final."
Adam Ling rowed a nicely-timed race in the non-Olympic lightweight single scull to pip reigning world champion Italian sculler Marcello Miani right on the line to make the semifinals.