What are the various methods of refloating a vessel ?

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1.Ground tackle
2.Tugs
3.Dredging craft
4.Even lighters into which to discharge of cargo.
5.Perhaps the hauling power of large vessels.
GROUND – TACKLE:  If vessel not in tidal water, secure vessel with ground tackle. This is meant for the use of anchors, carefully placed at considerable distances from the ship, and connected to her by heavy wire hawsers, possibly using some lengths of her chain cable. Heavy purchases are then rigged, often one secured to the hauling part of the other to give greater mechanical advantage and lower stresses on the final hauling part, to impose a stress upon these anchors. This stress, which must be applied continuously, is beneficial in re-floating the ship.
STATE OF TIDE:  While re-floating must be rising tide.
TIDAL RANGE : Check the draft of the ship and compare it with the estimated draught prior to impact. The difference in cm multiplied by the tones per cm immersion indicates the amount of lost of buoyancy. The tidal range may provide this required buoyancy at high water or even before.
DISCHARGED: Water tanks may be discharged in order to provide the required buoyancy.
NATURE OF BOTTOM: ideally, a survey should be made of the surrounding sea-bed, noting depths and material. The sea-bed formation in some localities changes with every tide making initial surveys unreliable. Some beaches are subject to strong cross-currents and scouring by surf. A survey will indicate the best possible direction for re-floating.
LEGAL SITUATION: The owners and Llyod’s  Agent should be informed as soon as possible. The underwriters will then be notified. At the next port of all protest should be noted, and a survey of the hull and machinery carried out. A certificate of Seaworthiness should be obtained before proceeding.