there was an incident on the Mississippi river two years ago where a ship was straining its mooring lines (run to several mooring bouys out in the river, also anchors down) in heavy current and squally wind. Several assist tugs came and the forwardmost one was pushing in to help hold this ship in berth, when the forces became too much and several mooring lines (heavy braided poly) parted.
In a freak accident, one end of the parted line recoiled back from the ship's shoulder chock, broke the tug's center window, and killed a deckhand inside the wheelhouse.
Always be careful around a line under tension. Unfortunately these lessons do tend to be learned the hard way.