Abstract: An anchor arm for anchoring a floating body, e.g. a semi-submersible platform, to a fixed anchor point pivotable about a vertical axis, comprises upper and lower articulated arms articulated to the floating body and anchor point respectively and a device for regulating forces transmitted to the arm comprising an articulated coupling connected across the articulation of the arm parts which is acted on by a float.

Abstract: A connecting structure for interconnecting a floating structure and a submerged anchor station is disclosed. This structure comprises an anchor cap which is adapted to be fixed to the anchor station and an arm which is pivotably connected to the floating structure. The pivotal connection to the anchor cap is by a ball and socket joint with the socket extending around more than half the lateral area of the ball. The cap is adapted to be pressed down to the enclosure by hydrostatic pressure.

Abstract: In a method of completing one or a plurality of grouped underwater oil wells, each well head to be connected is temporarily placed in a gaseous medium at atmospheric pressure during connection to effect this, prior to the installation of the well head, a structure is lowered vertically on to the sea bed where the gathering is to be carried out, the structure including an enclosure at atmospheric pressure and housing a manifold, and as many compartments, capable of communicating with the enclosure, receiving a production head and being rendered watertight, as there are well heads to be installed, each compartment being temporarily rendered watertight and filled with gas at atmospheric pressure during connection of the production head, previously placed in the compartment, to the manifold in the enclosure.

Abstract: A floating structure is anchored relative to the seabed by a rigid arm connected at one end to the structure and at the other end to a member, preferably in the form of an enclosure and including a watertight chamber for personnel, for pivotal movement about respective horizontal axes; the member is adapted to be releasably connected to an enclosure fixed in the seabed, defines with the enclosure a chamber to be placed at atmospheric pressure and is rotatable about a vertical axis relative to the enclosure. The arm may include damper means, e.g. in the form of a jack or a horizontal articulation of upper and lower arm parts.

Abstract: A quick release device for a line to be subjected to tension, and a method for using the device wherein a remotely generated control signal is received by a control signal receiver which acts to detonate an explosive charge thereby to open, remotely, a tension transmitter or link, in the line.