Underwater shackle for heavy loads, comprising a shackle body equipped with respective side plates (12a, 12b) and an upper, intermediate suspension for connection to a lifting strap, a lifting cable or the like, and also a lower locking bolt for connection to the load, - the locking bolt is movable arranged in a hydraulically driven cylinder arrangement, where the cylinder arrangement is placed adjoining one of the side plates, and where the cylinder arrangement is arranged to be pressurised by a pressure medium to move the locking bolt between a withdrawn position in the cylinder arrangement and a locking position in the shackle body, - the cylinder arrangement comprises an inner cylinder boring, where a piston part of the locking bolt is arranged for longitudinal movement in the boring, and a first inlet channel for supply of the pressure medium to a first side of the piston part, arranged for an outgoing movement of the locking bolt from the cylinder arrangement and also a second inlet channel for supply of the pressure medium to the other side of the piston part, arranged for ingoing movement of the locking bolt into the cylinder arrangement, wherein said underwater shackle further comprises - a pressure distributor to receive and distribute the pressure medium is arranged to the cylinder arrangement, where the pressure distributor comprises supply channels (44,46) that run together with said first and second inlet channels (34,36) in the cylinder arrangement, characterized in that the cylinder arrangement comprises a spring-loaded locking peg arranged to securely lock the locking bolt when it is in the locking position in the shackle body, the locking peg is coupled to, or integrated with, a locking plate which is movable arranged in the pressure distributor, and where a mouthpiece is arranged to trigger movement of the locking plate, and the locking plate comprises respective openings that lie in associated borings (42a,42b) in the pressure distributor and that a nose of the mouthpiece is arranged to be inserted into or taken out of said openings for raising and lowering, respectively, of the locking plate. - the locking bolt is movable arranged in a hydraulically driven cylinder arrangement, where the cylinder arrangement is placed adjoining one of the side plates, and where the cylinder arrangement is arranged to be pressurised by a pressure medium to move the locking bolt between a withdrawn position in the cylinder arrangement and a locking position in the shackle body, - the cylinder arrangement comprises an inner cylinder boring, where a piston part of the locking bolt is arranged for longitudinal movement in the boring, and a first inlet channel for supply of the pressure medium to a first side of the piston part, arranged for an outgoing movement of the locking bolt from the cylinder arrangement and also a second inlet channel for supply of the pressure medium to the other side of the piston part, arranged for ingoing movement of the locking bolt into the cylinder arrangement, wherein said underwater shackle further comprises - a pressure distributor to receive and distribute the pressure medium is arranged to the cylinder arrangement, where the pressure distributor comprises supply channels (44,46) that run together with said first and second inlet channels (34,36) in the cylinder arrangement, characterized in that