Mooring Lines

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Because Everybody Likes A Big Rope

Mooring line handling and operations are some of the most common practices aboard any ship. Whenever a ship comes along a dock, it tosses out lines. If the lines are put out wrong, it could kill someone. The lines are heavy and strong, but under the right conditions act just like rubber bands and snap back with enough force to cut someone in half. Knowing that, studying the proper procedures for tying up and letting go take on all that much more importance. Here are some basic things to know with mooring operations.
 
Mooring Arrangements:
  When a ship comes into port, the type of arrangement and number of lines that it will put out depends on the dock type and load condition of the ship. Most large cargo ships will often double up on all of their lines, putting out 2 each of the bow, bow and quarter spring, fore and after breast, and stern lines.
 
-Bow lines: typically run through the bull nose on the bow and run forward down the dock, leading ahead of the ship. When backed against, these lines will help to bring the ship in toward the dock.
 
-After bow spring: From the bow leading aft, these lines prevent the ship from surging forward should a ship's wake or wind force the ship ahead. Also, when run forward against, they will help to kick the stern out away from the dock
 
-Forward bow spring: From the after section of the bow leading forward, these help to prevent the ship from surging backward should a wake or wind force the ship astern. When backed against, they will help to pull the ship in to the dock.
 
-Breast lines: usually put out from the bow or stern, and occasionally amidships, these lines hold the ship alongside the dock. They do not prevent surging in any direction other than away from the dock, and are usually the last lines sent out and the first brought in.
 
-After quarter Spring: the lines run from the quarter aft and prevent the ship from surging forward. When pulled forward against, these lines help to pull the ship in toward the dock.
 
-Forward Quarter Spring: These lines run from the stern forward, and prevent the ship from surging aft. When pulled astern against, these lines help to push the bow out away from the dock.
 
-Stern lines: These lines run from the stern, usually run through the centerline chock, and run aft of the ship. When pulled forward against, these lines help to bring the ship alongside the dock.

mooring_lines.jpg

Mooring Line Commands:
-Pass One: send the first line over to the pier but do not take a strain
 
-Slack: pay out the line so that it is not under tension and it forms an easy bight
 
-Take a strain: heave on a line until it is under tension
 
-Take in the slack: heave on a line until the bight is removed, but do not take a strain
 
-Ease: pay out just enough slack to remove the tension from the line
 
-Avast heaving: stop heaving a line, but hold whatever tension currently exists
 
-Check: hold the current tension on a line by either paying out or heaving in as appropriate
 
-Hold: take enough turns about the capstan or bitt so that the line will not slip
 
-Double up: run additional lines or bights of lines as needed to make the mooring secure
 
-Single Up: take in all lines except whichever the captain specifies (usually the springs)
 
-Stand by the lines: man the lines, be ready to cast off or moor
 
-Take in: retrieve a specific line from the pier
 
-Cast off: remove the lines from the bitts or bollards