Only the top three in the semifinal moved on and the Canadians finished fourth. They started well but faded quickly and were fifth after 500, 1,000 and 1,500 metres. They posted the fastest last 500 but it was too little, too late.
China won in seven minutes 10.39 seconds, ahead of Denmark and Australia. Canada's time was 7:14.83. Britain, Greece and Germany moved out of the other semifinal.
"A tough one to swallow," said Jennerich, fighting to keep her composure behind wraparound sunglasses as she talked to reporters.
"It takes a little while to set in. ... I said to Obee, this might capture it well, it's like 'There's seven minutes of your life that suddenly take you out of a shot at an Olympic medal.'"
Jennerich and Obee had a poor start to the Games, finishing fifth in their six-boat heat. But the duo bounced back to finish second to the U.S. in their repechage Tuesday. The semifinal was another disappointment, however, denying Canada a shot at a medal.
The Canadian women's eight went for gold in the last race of the day. The men's eight won silver Wednesday.
The men's pair of Dave Calder and Scott Frandsen represents Canada's only other medal hope in rowing. They race in the final Friday.
Jennerich, who turned 30 on Monday, shared the boat with both 20-year-old Obee and 37-year-old Tracy Cameron of Shubenacadie, N.S., in the leadup to the Games.
In 2010, Jennerich and Cameron teamed up to win the world championship.
Last year they won in Lucerne, Switzerland, a major regatta ahead of the world championships. But when Cameron was sidelined with a stress fracture of a rib, Jennerich joined forces with Obee, the team spare, to win silver at the worlds.
Healthy again, Cameron won a row-off with Obee to see who would join Jennerich this year. But Jennerich and Cameron struggled when they got back in the boat, finishing eighth in May at a key pre-Olympic regatta in Lucerne.
Cameron, who won the lightweight quadruple sculls at the 2005 world championships and Olympic bronze in 2008 in the pair with Melanie Kok, retired in early June, saying rowing was no longer fun.
Jennerich said the pre-Games preparations were not ideal, "but it's what you make of it."
The circumstances "were handled like champions," she added.
In the women's lightweight class, rowers can weigh no more than 130 pounds and the crew average weight can't exceed 125.
The men's four of Michael Wilkinson of North Vancouver, Anthony Jacob of Victoria, Dean Will of Kelowna, B.C., and Derek O'Farrell of Montreal finished fifth in their semifinal and failed to make the final.
Michael Braithwaite of Duncan, B.C., and Kevin Kowalyk of Winnipeg finished last in a tough double sculls B final that featured 2008 Olympic champion Australia and world bronze medallist France. The Canadians finished the regatta in 12th spot.
NOTES — The men's eight got to eat Big Macs and meet Johnnie Mac after their silver medal performance Wednesday. CTV bought the rowers 140 pounds worth of McDonald's, allowing them to indulge a taste for junk food after months of good nutrition. Then the rowers met former tennis star turned commentator John McEnroe outside the International Broadcast Centre.
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