An outstanding display of sculling from Mathilda Hodgins-Byrne and Jess Leyden secured a second gold medal of the U23 World Championships for the GB Rowing Team in Rotterdam, the Netherlands.
Both the women's and men's eights won silver medals on Friday afternoon, while a late surge secured a second successive bronze for the lightweight men's four.
Today's medals, adding to the gold and silver won by the lightweight men's quad and men's four respectively on Thursday, took GB's tally up to six - matching their total from Plovdiv, Bulgaria last year.
Sir David Tanner, British Rowing's Performance Director and Overall Team Leader in Rotterdam, said: "With six medals, including two great golds and three strong silvers, we can be proud with our young rowers at these Championships.
"There is real promise in this team and I am sure that we have some exceptional talent here to challenge for senior team places at we start the Tokyo Olympiad."
Hodgkins-Byrne and Leyden already have senior experience and gave another demonstration of why they are so highly rated by finishing six seconds clear of the field in the women's double scull final.
"I can't believe how well that worked out!" said Hodgkins-Byrne. "This is my third go at the U23s and my first medal. It just felt different this year, we've felt really confident all the way."
On a good day for the Hodgkins-Byrne family, younger sister Charlotte helped the women's eight emulate the senior team's result at the Rio 2016 Olympic Games by finishing second to the United States.
Alice Bowyer, Emily Ford, Chloe Brew, Holly Hill, Madeline Badcott, Anna Thornton, Heidi Long and cox Sasha Adwani were also in the GB boat that pushed away from Russia in the third 500m to secure silver.
Long said: "I am so happy, I can't believe it. I don't think we could have asked for anything more, it feels absolutely amazing!"
The men's eight of Calum Irvine, Oliver Wynne-Griffith, Matthew Benstead, Timothy Livingstone, David Bewicke-Copley, Sholto Carnegie, Robert Hurn, Arthur Doyle and cox Ian Middleton weren't able to overhaul the front-running Dutch in their race but were pleased to get a silver medal.
Carnegie said: "We didn't get off to the best of starts but we put it all out there and kept pushing through to get a medal."
The lightweight men's four final was a repeat of last year with GB's Ed Fisher, Ben Reeves, Jonny Jackson and Alistair Douglass taking bronze behind Italy and Germany after a late sprint past Poland.
Douglass said: "We came here to try and win the gold but we knew it was going to be a top-class field, so we're pleased to go home with a medal."
It is the turn of the seniors to challenge for medals on Saturday, with five GB crews contesting the finals.
The women's four of Fiona Gammond, Donna Etiebet, Holly Nixon and Holly Norton race at 10.55am BST, followed at 11.10am BST by the men's coxed pair of Ollie Cook, Callum McBrierty and cox Henry Fieldman.
Britain are defending champions in both that boat class and the lightweight men's pair, with Joel Cassells and Sam Scrimgeour bidding to hold onto their title at 11.55am BST.
Brianna Stubbs, Emily Craig, Imogen Walsh and Ellie Piggott all won silver medals at last year's World Championships and will be looking to upgrade those in the lightweight women's quadruple scull final at 12.10pm BST.
The finals conclude at 12.25pm BST with Charles-Waite Roberts, Jamie Copus, Jamie Kirkwood and Zak Lee-Green racing for GB in the lightweight men's quad.
Saturday afternoon sees the focus move back to the Junior World Championships, with five GB crews racing in semi-finals - the women's four, men's four, women's quad, men's quad and men's pair.
U23 REPORTS AND QUOTES
Both Mathilda Hodgkins-Byrne and Jess Leyden have represented the GB Rowing Team at senior level and that experience and quality has shown in their women's double scull races this week.
Clear-water winners in both their heat and semi-final, the talented scullers - coached by Dan Moore - produced another outstanding performance to finish well clear of the field once again and secure GB's second gold of the week in emphatic style.
The defending champions from Romania adopted a 'glory or bust' approach to the final and held a narrow advantage at halfway. Belarus were also in the mix but Hodgkins-Byrne and Leyden were looking comfortable, hitting at a lower stroke rate than their opponents but matching their speed.
When they stepped on the gas with 800m to go, no-one was going to match them and they simply motored away to take the gold medal by some six seconds.
It is a second World title for Leyden, who won single scull gold at the 2013 Junior Championships, and a first medal at her third U23s for Hodgkins-Byrne, who began rowing at Hereford RC and is now part of the GB Rowing Team Start talent development programme at Reading RC.
"I can't believe how well that worked out!" said Hodgkins-Byrne. "From day one of training together, Dan told us how we were going to row together and that is exactly what we have done in every training session this summer.
"This is my third go at the U23s and my first medal. It just felt different this year, we've felt really confident all the way."
Leyden added: "I just got my head down and did what Mathilda told me to. Dan has told us all summer that the plan was going to work and it paid off big time, massive credit to him. It's been a very busy summer for both of us and it has ended in the right way."
The GB women's eight have won silver and bronze at the past two World U23 Championships and made it a hat-trick of podium places after taking silver - emulating the achievements of the senior eight at Rio 2016.
Again it was the United States who won gold with a dominant performance, leaving GB, Russia and New Zealand to battle it out for the other medals.
Russia held a narrow advantage at 750m but Charlotte Hodgkins-Byrne, Alice Bowyer, Emily Ford, Chloe Brew, Holly Hill, Madeline Badcott, Anna Thornton, Heidi Long and cox Sasha Adwani then began to move through the gears.
A concerted push took them nearly a length clear at 1500m and they had more than enough left in the tank to hold off a Russian challenge in the closing stages.
Long, in the stroke seat, said: "I am so happy, I can't believe it. I don't think we could have asked for anything more, it feels absolutely amazing. We wanted to try and chase down the Americans but the main focus was to get the nine of us down that 2k track as fast as we could.
"Our cox, Sasha, did an unbelievable job and everyone in the boat committed absolutely to every stroke she asked for, I'm so proud."
Thornton, a double World Junior medallist making her U23 debut, said: "That's probably the best race we could have put together, I'm really happy with what we've just done. We wanted to come off the water knowing we had put our best 2k out there and everyone is super, super pleased.
"The first thing we said when we got on the podium was it was the same finishing order as the Olympics, we're glad we could match the senior eight's result."
Coach Lauren Fisher, who also guided the women's four to within half-a-second of a podium place on Thursday, said: "We're really pleased with that. We've spent the whole time making sure we have a really solid first 1000m and have enough in the tank to challenge the Russians in the third 500m. We wanted to win but we knew it was going to be a tough ask against the Americans - maybe next year."
The men's eight of Calum Irvine, Oliver Wynne-Griffith, Matthew Benstead, Timothy Livingstone, David Bewicke-Copley, Sholto Carnegie, Robert Hurn, Arthur Doyle and cox Ian Middleton had produced a storming performance in their semi-final to go into today's medal showdown in confident mood.
They knew their biggest challenge was likely to come from the Netherlands and so it proved as the home favourites stormed out of the blocks, moving a length up on the field inside the opening 500m.
The British found themselves in fourth at that point but began to find their rhythm and pushed through the field, taking second spot with 750m to go. The Dutch had maintained their clear advantage, though, and it was only in the latter stages that GB began to create an overlap.
They were now the quickest boat on the water but had left it too late to challenge for gold, meaning the self-styled 'Shep's Army' - named in honour of their coach, Pete Sheppard - emulated the silver medal won by the GB women.
Benstead said: "We did the best we could do so we are very pleased with that result. All credit to Shep - there is a good mix of characters in this boat but he has brought us all together into a really good crew."
Carnegie added: "I'm really, really happy with that, it's my first World Championships medal at the third attempt. We didn't get off to the best of starts but we put it all out there and kept pushing through to get a medal."
Cox Middleton said: "It was a tough race and we gave it a good crack. The Dutch had a really strong race and managed to get off to a great start. We were quick but never really had quite enough to overturn them after that, so all credit to them."
It was the first U23 medal for a GB men's eight since 2011, when a crew featuring future Rio 2016 Olympic Champion Will Satch won bronze.
Ed Fisher, Ben Reeves, Jonny Jackson and Alistair Douglass were representing GB in the lightweight men's four for a second successive year, having won bronze in 2015.
They faced a host of familiar faces in today's final, with two of last year's title-winning Italian team also returning plus a couple of members of the Germany crew that won silver in Plovdiv.
And it was to be the same top three as last year but only after the British crew put in a massive sprint to overhaul Poland in the closing stages. With Germany and Italy charging away at the front, GB found themselves off the pace and were a length adrift in fourth at the halfway stage.
Britain upped their stroke rate but couldn't make any inroads into Poland's advantage and were still a length down with 500m to go. However, the pressure finally told and Fisher, Reeves, Jackson and Douglass were able to surge through to claim the third podium place.
Fisher said: "We were a length down with 500m to go but there was absolutely no way we were going home without a medal. It's just a shame we weren't a bit closer to Italy and Germany. We went out hard but they just went out harder and took each other away from the field."
Jackson added: "There were two crews who were more experienced than us and better than us on the day. We went out the intent of being in the mix when we sprinted. It didn't work out like that but we were able to hang on to Poland and we're pleased to come away with a medal."
Reeves said: "We did what we wanted to do in that race, executed the plan we had set out, and I could not have asked for any more from the boys. Italy and Germany were just faster than us on the day."
Douglass added: "Our times in training have been a lot quicker this year but you never know until you get to the championships how the other countries have stepped on. We came here to try and win the gold but we knew it was going to be a top-class field, so we're pleased to go home with a medal."
The men's quad of Harry Leask, Rowan Law, Harry Glenister and Andy Joel have stepped up their performances throughout the week, winning their repechage before comfortably progressing through their semi-final in third place.
They couldn't get into medal contention from the outside lane today - New Zealand storming through to snatch gold from Australia - but rowed well and finished on a strong note as they overhauled Germany in the last 100m to take fifth place.
Tom Barras demonstrated why he has been GB's leading U23 men's sculler this season with some eye-catching performances on his way to today's final.
Runner-up in awful conditions in his heat, he won his quarter-final by clear water and then enjoyed a great battle with Poland's Natan Wegrzycki-Szymczyk - seventh at the Rio 2016 Olympic Games - in the semis.
The Pole was favourite to win again but the whole field was stunned by an incredible front-running performance from Germany's Tim Ole Naske, who flew out of the blocks and somehow managed to maintain his pace throughout.
Barras sat in fifth place and held off a late challenge from Russia's Andrey Potapkin to secure that spot.
Sam Mottram was part of the GB lightweight men's quad that won silver at last year's World U23s, a performance that earned him a place at the Senior Worlds the following month.
This year he is racing in the lightweight men's single scull and qualified for the final with dogged performances in the quarters and semis.
The reallocation of lanes due to the cross-wind gave Mottram a tough task in lane six and he found himself off the pace as Belgium's Niels Van Zandweghe, Jonathan Rommelmann of Germany and Mexico's Alexis Lopez Garcia tussled for the medals - they eventually came home in that order after an absorbing battle.
Mottram kept plugging away and came home in sixth place overall.
JUNIOR REPORTS
A slight cross-wind led to lanes being reallocated for the morning session on Friday, which featured quarter-finals and repechages for the Junior World Championships.
The men's quadruple scull of James Mawby, Tom Digby, Josh Armstrong and Nick Plaut were up first for GB, getting off to a strong start as they and the United States opened up a healthy lead at 500m.
A push from the Americans moved them clear - they went on to take the win - and Denmark also upped their rate in the second 500m to edge ahead of the Brits.
Ukraine were also closing but Mawby, Digby, Armstrong and Plaut responded well and, roared by the vocal GB supporters, held off the sprint to take the third qualifying place for Saturday's semi-finals.
Alexander Wythe and Adam Teece also made good progress in the men's pair after producing a strong second half to their repechage.
The first 1,000m was very tight with just half-a-length separating all four boats in the field. New Zealand were the first to break clear, going on to take the win, but Wythe and Teece also put in a big kick in the third 500m and quickly regained momentum after a slight crab to secure the second semi-final place on offer.
There was disappointment for the men's double of Rory Harris and George Lawton as they finished a battling fourth in their quarter-final, putting them into the C/D semi-finals.
The Brits had won their heat in fine fashion but found themselves off the pace as Italy and Turkey quickly took control. Ireland were also going stroke for stroke with Harris and Lawton, with nothing to separate the crews at the 1,400m mark.
Ireland finally got their noses in front and, despite the best efforts of Harris and Lawton, were able to move away to claim the third semi-final place.