Abstract: A riser tensioner system maintains a tensile force in a riser having an axis and extending from a subsea wellhead assembly through an opening in a floating platform deck. The tensioner includes a plurality of tensioner legs having lower ends mounted to the deck, and upper ends having slots formed therein to receive leg attachment plates having an opening therein through which a tubular support ring passes. A plurality of cylinders extend between the tubular support ring and a tensioner ring and couple to the support ring with cylinder attachment plates through which the tubular support ring passes. An upper end of each cylinder pivots about the mounting point, and a lower end of each cylinder adjustably mounts to the tensioner ring.

Abstract: A system for lifting thrusters of vessels enabling for maintenance to be safely provided on the thrusters, wherein the system can include a lifting means with a line and a connector to engage thrusters or portions of thrusters. A transport device can be connected to the lifting means for transporting the thrusters or the portions of the thrusters. Clamps can secure thruster mounting flanges to thruster well bottom flanges. A conduit with a controller and a pump can allow water to flow into and out of the thruster wells. Seals adjacent the thruster mounting flanges can provide a connection between the flanges. A plurality of alignment guide plates can be disposed concentrically around the thrusters in the thruster wells and for a rough alignment of the thrusters to the thruster mounting flanges. Fasteners can secure the thruster mounting flanges to the thruster well bottom flanges.

Abstract: A riser tensioner system maintains a tensile force in a riser having an axis and extending from a subsea wellhead assembly through an opening in a floating platform deck. The tensioner includes a plurality of tensioner legs having lower ends mounted to the deck, and upper ends having slots formed therein to receive leg attachment plates having an opening therein through which a tubular support ring passes. A plurality of cylinders extend between the tubular support ring and a tensioner ring and couple to the support ring with cylinder attachment plates through which the tubular support ring passes. An upper end of each cylinder pivots about the mounting point, and a lower end of each cylinder adjustably mounts to the tensioner ring.

Abstract: A method is disclosed herein for lifting thrusters on vessels enabling for on vessel maintenance at sea. The method can include engaging a thruster mounting flange with a thruster well bottom flange; installing alignment guide plates to provide a rough alignment; positioning a seal to provide a connection; installing fasteners to secure the flanges; actuating clamps to secure the flanges while compressing the seal; raising the thruster out of the thruster well; transporting the thruster to a deck of the floating vessel; actuating clamps to hold the flanges; removing the fasteners; flowing water into the thruster well; disengaging the clamps; and lifting the thruster with the lifting means.