Abstract: In the automatic positioning of one submerged unit relative to another submerged unit without the use of guide lines, guiding structures associated with the units are brought into contact and the units are relatively orientated before the units are brought into contact.

Abstract: A leak-tight connecting device for the connection of two pipes comprising a primary ball-and-socket joint traversed by a bore, a secondary connecting support for said ball-and-socket joint, said secondary support comprising first and second outer sealing joints and a common central sealing joint located between said first and second outer sealing joints, each said sealing joint being disposed between said ball and socket joint and said support to define with said support and said ball-and-socket joint two chambers, means for connecting said chambers to a source of an incompressible fluid under pressure, mechanical means externally connecting said ball-and-socket joint and said secondary support, said mechanical means being pivotally coupled to each said joint and said support and operable to transmit torque from one of said joint and support to the other for various relative angular dispositions of said joint and said support and means for biasing at least one of said outer sealing joints bounding said chambe