The men's coxed pair added bronze, and Canada's team has a chance at more medals when a second day of finals draws the eight-day regatta to a close today.
"It was great to hear O Canada twice," head coach Brian Richardson said after the impressive Saturday showing. "There is excellent support and a real team effort going on here and these wins can only give those crews that row (Sunday) extra confidence."
Cam Baerg and Jake Wetzel of Saskatoon, Tom Herschmiller of Comox, B.C., and Barney Williams of Salt Spring Island, B.C., led all the way to win the men's four final in five minutes 52.91 seconds.
The 2001 world champions from Britain were second in 5:53.54, and the defending champion Germans were third in 5:55.13.
"Those two crews were favoured heavily over us," said Herschmiller.
He'd rowed in Canada's eight previously and, when he took last year off to work so he could repay some of his student loans, that crew won world gold.
Coach Mike Spracklen chose to keep the eight together so Herschmiller was slotted into the four.
"The most important thing Mike said to us was, 'If you guys think you deserve to be in the eight, you should win the four,' " said Herschmiller.
"Everybody who was slotted for the four in February decided this is it or nothing -- this is our boat and we have to prove ourselves in it."
The gold medal around his neck showed the mission was complete.
"I've been waiting a long time for this," said Herschmiller.
Milne, 31, a licensed physiotherapist from Niagara-on-the-Lake, Ont., who has trained in Australia for several years, led all the way in her lightweight singles final to win in 7:52.87.
Mirna Rajle of Croatia was second in 7:54.49 and Janet Raduenzel of Germany third in 7:56.53.
"It feels great," said Milne, who won Pan Am Games gold in a double earlier in the month.
"I hope I set the pace for everyone to follow."
Geoff Hodgson of Whitehorse and Kevin Burt of Ottawa with coxswain Brian Price of Belleville, Ont., who'll steer the eight today, won bronze (7:20.23) behind the United States (7:10.11) and Australia (7:13.13).