At low tide, the mooring line apparently got hooked on one of them.
From the sfgate.com
Then a mooring line from a ship slammed into his knee in 2005, ending his career as a load rigger.
From the thenewstribune.com
Once in, I kick hard for the front of the boat and catch the mooring line with a white-knuckle grip.
From the stltoday.com
Wilson then picked up a mooring line, pulled one end through the cleat loop and created a makeshift lasso.
From the newsobserver.com
The November incident occurred when the longshoreman was helping to dock an oil barge and a mooring line snapped.
From the timesunion.com
Using her capstans, Grapple can shorten or lengthen the mooring line for each leg and change her position within the moor.
From the en.wikipedia.org
After lunch, Lucy and I suited up and stepped off the boat's dive platform, sinking alongside the mooring line on to Hastings Reef.
From the telegraph.co.uk
The America's Cup World Series boat snapped its mooring line at Piers 30-32 that night and drifted off into the darkness, unmanned and out of control.
From the sfgate.com
First anchor it in the sea floor, and then up about several hundred feet with the mooring line, the riser pipe would come up to just below the surface, and there would be a buoy above it.