The GB Rowing Team has its first medals of the World U23 Championships - three silvers and a bronze - after an excellent afternoon of racing in Plovdiv, Bullgaria.
Richard Clarke, Ross Jarvis, James Johnston and Lewis McCue were involved in a thrilling final race of the day when they took silver in the men's four whilst Rowan McKellar and Holly Norton were earlier strong runners-up in the women's pair.
The lightweight men's quadruple scull of Steven Parsonage, Joel Cassells, Sam Mottram and Jamie Copus also won silver and there was bronze for the women's four of Emily Ford, Melissa Wilson, Holly Hill and Sam Courty.
Sir David Tanner, GB Rowing Team Performance Director, said: "We have had some very, very strong British performances this afternoon to take four medals from six starters.
"Credit to all of those crews and hopefully we will see more good performances from tomorrow's finalists."
The men's four of Clarke, Jarvis, Johnston and McCue have moved on with every race during the past three days and produced a great performance to contest the lead with the powerful Romanians for the first 1,500m.
Romania then edged ahead and Canada, who had beaten Britain in the heats, also put in a late challenge but Clarke, Jarvis, Johnston and McCue had done enough to get over the line in a well-earned second place.
Clarke said: "We really needed to step up as we came to the final through the repechages and we did it."
McKellar and Norton were second throughout the women's pair final as an impressive performance secured a silver medal.
With the outstanding American pair of Jessica Eiffert and Georgia Ratcliff setting a rapid pace at the front, McKellar and Norton concentrated on their own race and quickly established a clear-water advantage over the chasing pack.
They eventually crossed the line five seconds clear of third-placed Australia and Norton said: "It's great to be on the podium. It was a tough but good race, it went by so quickly."
The second GB silver went to the lightweight men's quadruple scull of Parsonage, Cassells, Mottram and Copus.
They were a narrow fourth at the 1km mark but put in a big push to row through both the German and Danish crews and take second place by 1,500m.
France had led by clear water from the early stages but found themselves being reeled in by the British crew, whose storming finish cut the winning margin to just three-quarters of a length.
It is a third successive silver medal at the World U23 Championships for Cassells, who was part of the lightweight men's four in both 2013 and 2014. Copus was also in the four last year.
"We are disappointed not to win gold but the French were just on another level," said Cassells. "I am very proud of the crew, though. We had a good race."
The first GB medal of the championships went to the women's four of Ford, Wilson, Hill and Courty, who finished third in their final.
As in their previous two outings, the British crew took the race by the scruff of the neck and matched the United States stroke for stroke for the first 600m.
The US, looking to defend the title won 12 months ago in Varese, edged ahead and a big push from the Canadians took them into second place.
However, the British four had established themselves in the medal positions and were untroubled by a late sprint from Australia as they took bronze in 6:56.83.
"It's awesome," said a delighted Courty. "We had a good start and then we just stuck to the plan."
It was a second successive World U23 Championships medal for Courty and Ford, who were part of the women's eight that won silver in 2014 while Wilson and Hill represented Cambridge in the first Women's Boat Race this year.
Courty and Hill are also part of the GB Rowing Team Start Programme, an innovative and successful talent identification and development initiative through which, since 2001, rowers like Helen Glover, Moe Sbihi, Sam Townsend and others have emerged to win either Olympic or World medals.
The lightweight women's quad of Maddie Arlett, Ellie Lewis, Flo Pickles and Lucy Cruxton finished just outside the medals in their final.
Italy were clear winners after a powerful performance but the British crew were in touch with Germany and France throughout in the battle for the podium places.
They were closing in on third place around the 1,250m mark but France responded to the threat and went on to pip Germany to silver, with the British crew fourth in 6:56.08.
James Goble and Tom Marshall had to settle for fifth place in the lightweight men's pair final after being overtaken by a fast-finishing United States crew in the closing stages of their final.
The British pair had sat in fourth for most of the race behind Italy, Turkey and Greece, who went on to take gold, silver and bronze respectively.
Sunday's A finals get under way at 8.40am BST with James Rudkin and Tom George in the men's pair, followed by Georgia Francis and Mathilda Hodgkins-Bryne in the women's double scull at 8.55am.
The lightweight men's four of Ed Fisher, Ben Reeves, Jonathan Jackson and Alastair Douglass contest their final at 9.25am and Jack Beaumont goes in the single scull at 10.25am.
The championships conclude with the eights finals, with the women racing at 10.40am and the men at 11.10am.