Abstract: The invention relates to a pivotal connecting device of the kind forming a universal Cardan joint coupling in particular for a compliant or articulated column of a sea-bed working structure, said column being pivotally connected to a base member, wherein said universal Cardan joint coupling is associated with one or more rigid connecting ducts for conveying the flow of at least one fluid between said base member and said column.

Abstract: A fluid-tight sealing device for elements which have a common axis are capable of angular displacement relative one to another, and which define an enclosed space comprises a sleeve arranged for co-axial disposition relative to said elements to be engaged endwise between support surfaces provided on the elements. The sleeve is formed by rigid rings having rings of elastomeric or resilient material interposed therebetween and when in position between the support surfaces the sleeve is axially stressed in compression and is so disposed that it permits angular displacement of the elements by relative angular movement of at least one end of the sleeve in relation to the support surface engaged thereby, by torsional elasticity of the sleeve, or by a combination of both angular movement and torsional elasticity.