Abstract: The present invention relates to a method for laying a pipeline using a vessel (1) comprising a crane (2) comprising the following steps lifting a new pipe section (8) using the crane, placing a new pipe section on an existing pipeline (9), lining up the new pipe section with respect to the existing pipeline, welding the new section to the existing section, lowering the joined new section and the existing pipe, supporting the joined new section so that the crane is free to lift another new section. The invention further relates to a pipe-laying vessel for carrying out such method.

Abstract: The present invention relates to a method for laying a pipeline using a vessel (1) comprising a crane (2) comprising the following steps lifting a new pipe section (8) using the crane, placing a new pipe section on an existing pipeline (9), lining up the new pipe section with respect to the existing pipeline, welding the new section to the existing section, lowering the joined new section and the existing pipe, supporting the joined new section so that the crane is free to lift another new section. The invention further relates to a pipe-laying vessel for carrying out such method.

Abstract: The invention relates to a method and device for constructing a pipeline with an in-line or add-on device from a pipeline laying vessel, the method comprising the steps of: (a) suspending the pipeline from a clamping device on the vessel; (b) connecting an in-line or add-on device to the pipeline above the clamping device; (c) moving at least part of the clamping device away from the pipeline to provide clearance at the pipeline; (d) lowering the pipeline by a pipeline, deployment device until the in-line or add-on device has moved beyond the clamping device.

Abstract: The invention relates to a method for assembling and disassembling an installation present on a seabed, for instance a pipeline lying on a seabed, wherein components, for instance pipe flanges, are mutually attached by means of nut and bolt connections and the nut and bolt connections are released and/or secured by means of a wrench. Nut and bolt connections are herein released by divers using a wrench. This is heavy and difficult work. It is impossible for divers to operate at considerable depth. Complicated and very costly pipeline connections are then applied which can be released and secured without divers. The invention has for its object to reduce the stated drawbacks of the known method. To this end at least one wrench is used, of which an engagement cup for engaging a nut and/or a bolt head in axial direction of a nut and bolt connection for manipulating is displaceable relative to a cup carrier counter to spring action.

Abstract: A method for lifting a sea platform with its substructure attached from a seabed and moving that platform to a different location. Use is made of flotation bodies which are filled with water and attached to the substructure. The flotation bodies can be emptied of some water to provide greater flotation and can be rotated around a horizontal axis to facilitate movement of the entire assembly under various sea conditions.