"It is very sad news," performance director David Tanner told British Rowing's official website.
"Acer was the top British cox of his time. He had an exceptional period with the GB rowing team."
The cause of death was not disclosed but media reports said Nethercott had been fighting brain cancer.
Nethercott coxed the men's eight crew that came second in the 2008 Olympics in Beijing, the culmination of a glittering career on the water that saw him guide Oxford to Boat Race victories in 2003 and 2005.
The Essex-born Nethercott, who earned a PhD in linguistics in his time at Oxford, began crewing for Britain in 2005, and won gold, silver and bronze medals in World Cup and World Championship races before the silver in Beijing.
He stepped away from the sport after that but returned a few years later to get in contention to cox the men's eight at London 2012 before the role was given to Phelan Hill.
Nethercott's unusual Christian name means "fierce, keen and eager" in Latin, and former team-mates took to Twitter to pay tribute to a man who lived up to his name.
"A privilege to have known him, he lived up to the meaning of his name in every way," said 1992 gold medal-winning cox Garry Herbert, while the Great Britain rowing team wrote, "Keen, eager & spirited like his name. Great member of GB Rowing Team. Thoughts are with family."