Acts 27:28-29

So they took soundings [using a weighted line] and found [the depth to be] twenty fathoms (120 feet); and a little farther on they sounded again and found [the depth to be] fifteen fathoms (90 feet). Then fearing that we might run aground somewhere on the rocks, they dropped four anchors from the stern [to slow the ship] and kept wishing for daybreak to come.