The oil tankers are carrying up to 250,000 tonnes of crude oil
There are currently more oil tankers moored off the south Devon coast than at any time since the 1980s, a local shipping agency has said.
There are now 10 tankers, each carrying up to 250,000 tonnes of crude oil, anchored in Lyme Bay, near Brixham.
Master Mariner Paul Wright, from the University of Plymouth, said they were waiting for world oil prices to rise.
Shipping agent, Jerry Carter, said crews from the tankers were boosting the local economy.
Mr Wright, associate director of the University of Plymouth's Marine Institute, said: "Up to 60 tankers around the world are currently being used as storage tankers in anticipation of oil price rises.
We've got one that's been here eight weeks
"The owner is happy because he's getting money for his ship and the speculators are happy too.
"They'll just sit and wait for the market to go up."
Mr Carter, from Torbay and Brixham Shipping Agency, said: "We've got 10 tankers out here at the moment, fully manned, ready to go.
"Ships know Lyme Bay is a good area to anchor in because it's sheltered.
"Some are here a couple of weeks, but we've got one that's been here eight weeks."
Mr Carter said his firm, which provides pilot boats and other maintenance services for the tankers, tries to promote local businesses where it can.
"Crews are also coming to shore and using local doctors and hairdressers and taxi firms etc," he added.
"People don't realise how much this contributes to the local economy."
Once the oil is sold tankers will head to refineries to unload.