Ship Mooring is the system for securing a ship to a terminal. It can be with anything such as Jetty, Ship, Buoy, Pier, etc. Mooring is done for various purposes like while transiting canal, securing to fixed or floating platform (jetty, ship, buoy, pier) for cargo operation, Towing and for many other purposes. Normally a ship is moored by head, breast, spring and stern lines which prevents the ship movements.
Ship Mooring Lines
Mooring Lines are used to secure the ship at berth. Mooring arrangement should be plan with all the proper precautions.
Head lines prevent both forward and lateral movement, these are the lines leading ashore form the forward end or forecastle of a ship.
Breast lines prevent the lateral movement of the ship, these are the lines which are leading ashore as perpendicular as possible. These are on both places forward and aft.
Spring lines prevent forward and aft movement of the ship. Forward spring leads aft to the ashore preventing forward movement and Aft spring leads forward to the ashore preventing Aft movement.
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Stern lines prevents both aft and lateral movement, these are the lines leading ashore form the after end or poop deck of a ship.
Types of Ship Mooring
Ship to Ship Transfer
In this type of mooring two ships are moored alongside for the purpose of cargo transfer. This ships can be same or different in size. The mooring arrangement to be adopted depends on the size of the ships. Normally in this type of mooring one ship is maintaining her course or anchored and the other vessel join her. They should be aligned with each other in such a way that there is not much of lines chaffing against each other. While approaching for STS transfer wind and current should be from bow.
Single Point or Single Buoy Mooring
This mooring is for tankers, in which there is a buoy where the ship is moored. Usually this types of mooring is used for large ships which are unable to approach ports. The buoy is connected to the ship with one or two chains from the ship bow stopper at the forecastle. Ship slowly approach towards the buoy meanwhile ship is made fast to the buoy. Approach towards the buoy when ship is about 200 meters from the buoy. Often a tug is made fast in the stern to prevent the movement of the ship.
Multi Buoy Mooring
As the name suggest in this mooring a ship is moored by multiple buoys that are fixed to the seabed. But sometimes in addition to the buoys ship’s own anchors are also used. It is also known as conventional buoy mooring. Normally buoys are fixed in a rectangular form. This mooring is used when there are limited quay facilities.
In this type of mooring ship is moored with both of her anchors in conjunction with stern lines. This type of mooring requires less space in the jetty because only her stern is moored to the jetty. First the anchors are dropped and then with the help of engine stern swings towards the jetty and made fast. Ship is kept at position with the help of anchor.
This mooring is done in windy condition and when proper provisions are not available for these conditions. Ship’s anchor and stern mooring line is used to moor the ship. In the offshore, anchor is paid out up to ganger length and mooring rope coming from the aft will be tied to that ganger length point. Now with the effect of wind and engine ship will move towards the jetty in athwartship direction while paying out the anchor chain and aft mooring rope. Then ship will be moored to the jetty by passing head, breast, spring and stern lines. Accordingly anchor cable and aft mooring rope will be paid out so that it become taught and hold the ship.
Ganger Length: A short length of the ship’s anchor cable which is found between the ‘Anchor Crown ‘D’ Shackle’ and the fist joining shackle of the cable.
This type of mooring takes less time then the Mediterranean mooring. In this mooring ship will go against the tide and the stbd anchor is let go while moving ahead at slow speed. Once the ship starts moving astern due to tide the port anchor is let go while simultaneously heaving up the stbd anchor and stop once the ship is at her desired position. In this mooring more control of the ship can be achieved.
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In this mooring once ship is stop, she will let go port anchor and with the effect of wind goes back pay out the port anchor upto 9 shackles then let go stbd anchor and simultaneously heave up port anchor and stop once the ship is at her desired position. This process take longer duration than running mooring and less control over ship.
Onboard ship mooring is one of the most hazardous job. Mooring team should be very careful while doing it. All the crew involved in mooring operation should have worn Proper Protective Equipment (PPE).
I hope you understand now what is mooring and it’s types. If you have any doubt do let us know in the comment section.