
A mooring refers to any permanent structure to which a vessel may be secured, such as quays, wharves, jetties, piers, anchor buoys, and mooring buoys. A ship is secured to a mooring to forestall free movement of the ship on the water. An anchor mooring fixes a vessel’s position relative to a point on the bottom of a waterway without connecting the vessel to shore. As a verb, mooring refers to the act of attaching a vessel to a mooring system.
Types of Mooring
SHIP-TO-SHIP
This type of mooring is used between two vessels, with no dock or buoy involved. This is done to transfer cargo or to take bunker. This type of mooring can be done when one of the vessel is at anchor and another vessel approaches it or when both the vessels are in motion. Bunkering in this manner is very common.

SINGLE POINT OR SINGLE BUOY MOORING
This mooring method consists of a floating dock or buoy outside the port to handle liquid or gaseous cargo from ships like oil vessels.

MULTI-BUOY MOORING
Also, known as Conventional mooring. In MULTI-BUOY MOORING type of mooring, vessel is secured with both its anchor and Aft part of the vessel is secured to a buoy.
BALTIC MOORING
Baltic mooring is a combination mooring of a vessel alongside the berth which employs a stern mooring shackled to the offshore anchor cable in the region of the “ganger length”. When approaching the berth, the offshore anchor is deployed and the weight on the cable and the stern mooring act to hold the vessel just of the quay. Baltic mooring is a safe option to berth a ship on a windy day.
Running Mooring
This maneuver takes relatively short duration compared to the Mediterranean mooring and offers more control of the vessel. The vessel’s starboard anchor is let go at a position approximately four to five shackles from the final position of the bow and around 9 shackles paid out while moving ahead on engines. Then as she falls astern with the tide the port anchor is let go and the starboard anchor is heaved on to five shackles. This method restricts the swinging room and reduces the load on the windlass.

http://www.oocities.org/mpaoral/ch5/moorings.htm
Standing Mooring
This is practised during crosswinds. As the vessel is stopped the port anchor is let go and with the tide around 9 shackles are paid out. The starboard anchor is let go and simultaneously port anchor heaved on. Thus the port anchor is kept on 4 shackles being generally the flood anchor and starboard on five as it is the ebb anchor. This vessel takes longer duration and provides less control over the vessel. The load on windlass is more as compared to running moor.

http://www.oocities.org/mpaoral/ch5/moorings.htm