A steel plate and concrete composite tank unit, tank groups and offshore platforms with new type of tank units are disclosed. The tank unit comprises an outer concrete tank that comprises an outer tank shell, two heads and ring shell connections at both ends, an inner steel tank that comprises an inner tank shell, epitaxial structures at both ends of the inner steel tank. Inner tank shell is connected to the outer tank shell by epitaxial structures, and an isolation layer that is formed from the gap between the outer concrete tank and the inner steel tank where it is filled with isolation medium.

A stone dumping vessel having symmetrical stone compartments includes a hull, a stone conveying unit, and an oblique fallpipe unit. The hull has a control cabin. A cannula compensating device of the oblique fallpipe unit is disposed on a side of the hull and connected with a fallpipe. Two sides of the control cabin are symmetrically provided with the stone compartments and dynamic positioning (DP) system cabins, respectively. The stone compartments are operated independently for automatically unloading stones to the stone conveying unit disposed at a lower center thereof. The stones are conveyed by independent conveyor systems disposed at the left and right of the control cabin to the fallpipe. The dynamic positioning (DP) system cabins and the cannula compensating device are adapted to position the hull and the fallpipe respectively so that the stone dumping vessel having symmetrical stone compartments can achieve high accuracy of stone dumping.

An underwater base handles an autonomous underwater vehicle. The underwater a support structure to be hooked to a cable, a storing part configured to store the AUVs, an inlet part located above the storing part and configured to control access of the plural AUVs to the storing part, and a control part configured to control a movement of the inlet part relative to the support structure. The control part is further configured to wirelessly guide the AUVs while approaching the inlet part.

A casing assembly for forming a cast-in-place pile (CIP) retaining wall based on a CIP method. The assembly comprising: a hollow elongate cylinder having a hollow cylindrical inner space defined therein; a H-beam guide received within the hollow cylindrical inner space of the hollow elongate cylinder; and a first H beam having a vertical column form and inserted into the H-beam guide, wherein the H-beam guide includes: a hollow beam-guide frame having a rectangular cross-section such that the first H beam is insertably guided in and along the hollow beam-guide frame; and an outer rounded frame coupled to an outer face of the hollow beam-guide frame, wherein an outer face of the outer rounded frame conforms to an inner face of the hollow elongate cylinder, wherein a top portion of the outer rounded frame is fixed to a top portion of the hollow elongate cylinder via a fastening flange.

An assembly includes a fastening screw having an end surface and a substantially cylindrical side surface extending axially away from the end surface and a protective cap covering the free end. The cap has a first end opening from which the fastening screw extends, a second end overlying the end surface of the fastening screw, a side wall surrounding a portion of the cylindrical side surface, an inner surface defining a cap interior, and an outer surface. A cap screw extends through an opening in the second end of the cap and into a threaded opening in the end surface of the fastening screw to secure the protective cap to the fastening screw.

The present invention relates to a method for lowering a subsea structure to be installed on the seabed into the water through the splash zone, said subsea structure comprising subsea equipment arranged on a substantially flat support base for preventing the subsea equipment to sink into the seabed. The method according to the invention comprises: lifting the subsea structure into the air in a horizontal position in which the flat support base extends substantially parallel to the horizontal plane; tilting the subsea structure while suspended in the air from the horizontal position into a tilted position in which the flat support base is angled with respect to the horizontal plane; lowering the subsea structure into the water through the splash zone in the tilted position; and tilting the subsea structure while suspended in the water below the splash zone back into the horizontal position.

A foundation structure of an offshore plant, such as a wind turbine, comprising at least one foundation element that can be anchored to the seabed without a gravity foundation and without a floating foundation and a support structure fastened thereto for fixing the offshore plant. The foundation element is a pile that can be inserted into the seabed by means of drilling and/or by means of vibratory driving, can be fixed in the seabed by means of an organic and/or inorganic material, and is oriented at an angle from a vertical on the seabed. A method of installing the foundation structure on a seabed includes first anchoring the coupling element by means of piles inserted into the seabed and then connecting the support structure to the coupling element.

A sub-sea power supply includes a plurality of transformers, a wet-mateable connector, and a plurality of passive rectifier circuits. Each transformer includes a primary coil and secondary coil. The primary coils are coupled in parallel. The wet-mateable connector is coupleable to a sub-sea AC power source. The wet-mateable connector is coupled to the primary coils. The plurality of passive rectifier circuits is respectively coupled to the secondary coils. The plurality of passive rectifier circuits is configured to generate substantially uniform polarity voltage outputs coupled in series.

A coating film capable of being peeled off in the shape of sheet to facilitate a coating film removal work, and is less likely to peel even after long periods of use on an underwater structure is provided. The coating film comprises an undercoat layer to be bonded to an underwater structure, and an antifouling layer bonded to the undercoat layer, wherein: a 100-gram underwater constant load peeling degree of the coating film is less than 5; a ratio of a tensile breaking strength of the coating film to an adhesive force of the coating film with respect to the underwater structure, as measured after immersing the coating film in pure water at 60 C. for 5 weeks is 1.5 or more; and a 1-mm square cross-cut stretching-caused peeling degree of the antifouling layer with respect to the undercoat layer is 0.05 or less.

A cofferdam is disclosed that includes an open frame structure having double walls defining a hollow space within each double wall, with each double wall having an open bottom end and a closed top end. Each of the double walls are configured to act as suction piles allowing liquid to be removed from the space within each double wall to thereby induce negative pressure when the cofferdam is installed in a sub-sea configuration. Each of the double walls may include a plurality of partitions respectively defining a plurality of suction piles, the suction piles fluidically coupled by a manifold that may allow liquid to be removed from the suction pile to thereby drive the cofferdam structure into the subsea surface due to the induced negative pressure. A further embodiment cofferdam structure includes an open frame structure and one or more suction piles attached to the open frame structure.