Britain's paddlers missed out on medals in two finals on Friday.
Tim Brabants went into the men's K1 1000m singles final as the fastest qualifier but he could not stay with the pace when it mattered.
And he had to settle for fifth in a time of three minutes 30.553 seconds. Norway's Eirik Veraas Larsen took gold.
Meanwhile, Paul Darby-Dowman and Ian Wynne were seventh in the men's K2 1000m final - Markus Oscarsson and Henrik Nilsson of Sweden won the gold.
Brabants, a bronze-medallist in Sydney, had high hopes of a top-three finish after his impressive form earlier in the week.
And he was at a loss to explain his lacklustre display in the final.
"I really thought I could improve on Sydney," he said. "I prepared well and I knew from the heats that I was going perfect.
"I knew it was going to be a fast race from the start and I tried to be strong at the finish to try to pull back some time, but on the day there were four guys better than
Wynne, who also competes in Saturday's K1 500m, and Darby-Dowman were not too disappointed with their performance.
"We had a really good race. We didn't do anything wrong but the
other guys were faster than that," said Wynne.
In the men's C1 1000m final, Spaniard David Cal won the gold medal, ahead of Germany's defending champion Andreas Dittmer, with Hungarian Attila Vajda third.
But German duo Christian Gille and Tomasz
Wylenzek came from behind to just edge out Russia and win the gold medal in the men's C2
Wynne and Darby-Dowman won European bronze in May
Pre-race favourites world champions Romania faded badly and finished fourth, while
Hungary took the bronze.
Hungary went two places better in the men's K4 1000m, winning the gold medal ahead of Germany. Slovakia bagged the bronze.
Birgit Fischer then ensured it was a golden morning for Germany when she guided her crew to victory in the women's K4 500m event to win her eighth Olympic gold medal.
Hungary secured the silver medal and Ukraine took the bronze.
Fischer, 42, was adding to a collection she started 24 years ago when she won the K1 500m in Moscow.