Authorities are searching for an Olympic sailor whose empty boat was found floating, still in gear off the coast of Miami Thursday.

Trevor Moore, 30, competed in the 2012 London Olympics. Friends say he took an inflatable dinghy out in the Biscayne Bay on Thursday around 1 p.m.

That was apparently the last time anyone saw him—the boat was reportedly found empty, tangled up in moorings around 5 p.m. Via CBS:

Among the items found on the inflatable boat were a life jacket and a GPS. A source told CBS4 the GPS showed that the [boat] reduced speed by Soldier Key, south of Stiltsville, and zig-zagged back to where it came from. It’s believed that Moore was off the boat at that time.

Leira, a sailing coach, said he’s concerned. He said it’s not difficult to be knocked off an inflatable.

“If you’re traveling at a high rate of speed, it’s very easy to fall off unless you have a safety band, you can easily fall off the boat and the boat can keep moving if you are not on board,” said Leira.

At least four agencies are involved in the search, which reportedly involves helicopter support and at least eleven boats.

Image via AP. Contact the author at gabrielle@gawker.com.