An underwater plough and a method of operating an underwater plough is disclosed. In particular, an underwater plough for providing an elongated element into a submerged surface and a method of providing an elongated element into a submerged surface is disclosed, the underwater plough comprising a body portion, a plough share extending from an underside of the body portion, the plough share comprising a cutting edge for cutting a bottom of a trench in which the elongated element is to be deposited, support means and actuating means. The underwater plough is configured such that actuation of the actuating means within an operational configuration varies the first direction and the second direction changing the orientation of the longitudinal axis of the body portion with respect to the contact plane and/or the distance between the body portion and the contact plane while the underwater plough is supported by the support means.

Disclosed is an underwater laying device for offshore oil and gas pipelines. By using a steel cuboid as the main body, a first mud-ploughing rake, a first mud-ploughing hoe, a second mud-ploughing rake, a second mud-ploughing hoe, and a mud delivery plate are disposed on the lower surface of the cuboid main body. Further, by cooperation of a mud collection hood and an elongated pipeline-delivery cylinder, and according to structural characteristics of traditional farming tools, submarine trenching, pipeline laying, and pipeline burying can be successively performed and all implemented by the device of the present invention. Further disclosed is a pipeline laying method of the device of the present invention. The device of the present invention has a simple structure, and overcomes the structural complexity of the conventional underwater robot on the premise of achieving the function requirements, thus greatly reducing the manufacturing cost and being mass-producible.

Disclosed is an underwater laying device for offshore oil and gas pipelines. By using a steel cuboid as the main body, a first mud-plowing rake, a first mud-plowing hoe, a second mud-plowing rake, a second mud-plowing hoe, and a mud delivery plate are disposed on the lower surface of the cuboid main body. Further, by cooperation of a mud collection hood and an elongated pipeline-delivery cylinder, and according to structural characteristics of traditional farming tools, submarine trenching, pipeline laying, and pipeline burying can be successively performed and all implemented by the device of the present invention. Further disclosed is a pipeline laying method of the device of the present invention. The device of the present invention has a simple structure, and overcomes the structural complexity of the conventional underwater robot on the premise of achieving the function requirements, thus greatly reducing the manufacturing cost and being mass-producible.

A depressor (16) for inserting a cable (4) into a trench (6) is disclosed. The depressor (16) comprises a plurality of cable shoes (22) adapted to be mounted to a support (18) and to engage the cable (4). Locating pins substantially prevent movement of the cable shoes (22) relative to the support (18) in a first direction as a result of movement of the cable shoes (22) relative to the cable (4) in an axial direction of the cable (4). A load cell provides an output dependent on a force applied to the cable shoes (22) in a second direction transverse, or perpendicular, to the first direction.

A device for providing an elongated element in a seabed is disclosed. The device comprises a main body having trench forming means for forming a trench in a seabed, and a receiving section for receiving an elongated element. The main body is adapted to guide said elongated element, from said receiving section, into a trench formed by said trench forming means. The device further includes supporting means defining a contact surface for supporting said main body with respect to said seabed, wherein the receiving section is configured to receive the elongated element from a side substantially opposite to the contact surface along a loading path. The device further includes a drawbar connected to said main body. The drawbar is movable from a loading position to a towing position. In the towing position said device is towable in a trenching direction via a towing line connected to said drawbar. In the loading position the drawbar is spaced apart from the loading path to allow the elongated element to be loaded into the receiving section along the loading path.