Patience and Bithell handled the varied conditions well in the medal race
Great Britain's Luke Patience and Stuart Bithell took silver at the 470 World Championships in Denmark.
The pair, who only teamed up two weeks ago, came fourth in the medal race to finish second overall behind the team from Croatia and ahead of Japan.
"I am ecstatic, I can't believe it!" said 23-year-old Scotsman Patience.
"Teaming up with Stuart just the week before, we'd done five days sailing before race day one so we are extremely happy with hopefully more to come."
Fellow Britons Pippa Wilson and Saskia Clark, and Penny Clark and Katrina Hughes, also secured top-10 finishes in their debut event as teams.
Wilson and Clark finished ninth in the medal race to take eighth spot overall, while Clark and Hughes were 10th in the medal race to finish ninth.
Of the other British crews, Nick Rogers and Pom Green were 17th, Ben Saxton and David Kohler 18th, and Nic Asher and Elliot Willis 19th, while in the women's fleet Hannah Mills and Rosie Chapman were 19th, and Sophie Ainsworth and Sophie Weguelin 24th.
Meanwhile, Ed Wright had to settle for bronze at the Finn European Championship after the final medal race was cancelled due to poor weather conditions in Varna, Bulgaria.
"It was pretty disappointing that I didn't get the chance to fight for silver today, but I'm happy with my third," said Wright, who won the European title in 2006.
"I think the race officer made a good decision to call it off, especially in light of the trick and random conditions we had yesterday."