Shipping line Maersk claims it has made the first UAV delivery at sea.

Maersk used a rotary-wing UAV from Xamen Technologies to deliver cookies to the tanker Maersk Edgar off the Danish coast, according to a company news release.

"Costs for a barge are on average $1,000 and can be higher," Maersk said. "That means drone use could with the current payload bring potential savings of $3,000 to $9,000 per vessel per year."

"It's a totally new step in delivery to vessels," said Peder Georg Kastrup Christensen, the Maersk Edgar's captain. "Today it's cookies. Another time it might be medicine which we need to treat someone on board."