The next day the two see the boat is drifting away.
Well, someone would see this boat drifting before too long.
"A boat would likely drift in and get caught up on one of them."
The boat drifted past, carried near them by the current.
The boat drifted, as if it had lost its sense of direction.
Next thing I know they find his boat drifting in the ocean.
Her boat was drifting with the current, the engine off.
The boat drifted to a stop at the edge of the ice.
For eight days the boat drifted, carried by the current under the conditions already described.
In 1991, a small boat drifted too close and fell over one part of the dam.