Systems and methods for securing a remotely operated vehicle (ROV) to a subsea structure during cleaning, maintenance, or inspection of the structure surface are provided. In one or more embodiments, an attachment mechanism includes a pair of grasping hooks that are raised and lowered when driven by a motorized drive. In one or more embodiments, an attachment mechanism includes a rigid holder having a mechanical stop and connected to a swing arm, the swing arm configured to rotate inward, but not outward beyond the mechanical stop. In one or more embodiments, an attachment mechanism includes a plurality of linked segments in series, each connected at a plurality of pivot points. A pair of wires passes through the plurality of linked segments and connects to a pair of pulleys that extend or retract the wires, thereby rotating the plurality of linked segments.

A hydraulically powered rotary actuator is described including: a hydraulic linear actuator which is moveable in both directions between a retracted position and an extended position; a clutch device which is operable between an engaged condition and a disengaged condition; and a rotary output member; wherein the linear actuator is coupled to the rotary output member by way of the clutch.

A hydraulically powered rotary actuator is described including: a hydraulic linear actuator which is moveable in both directions between a retracted position and an extended position; a clutch device which is operable between an engaged condition and a disengaged condition; and a rotary output member; wherein the linear actuator is coupled to the rotary output member by way of the clutch.

An inspection crawler, and systems and methods for inspecting underwater pipelines are provided. The system includes the inspection crawler having a housing with a first side, an opposing second side, a power source, and a controller. The crawler includes an inspection tool, at least two pairs of latching arms, each latching arm including a rolling element, and at least two pairs of driving wheels. The system also includes at least one communication unit configured to communicate with the inspection crawler and to communicate aerially with one or more remote devices and, and at one sea surface unit. The inspection crawler can further include a connecting structure connecting the front and back portions of the crawler, and configured to elongate and shorten the inspection crawler.

An inspection crawler, and systems and methods for inspecting underwater pipelines are provided. The system includes the inspection crawler having a housing with a first side, an opposing second side, a power source, and a controller. The crawler includes an inspection tool, at least two pairs of latching arms, each latching arm including a rolling element, and at least two pairs of driving wheels. The system also includes at least one communication unit configured to communicate with the inspection crawler and to communicate aerially with one or more remote devices and, and at one sea surface unit. The inspection crawler can further include a connecting structure connecting the front and back portions of the crawler, and configured to elongate and shorten the inspection crawler.

A Stirling cycle machine. The machine includes at least one rocking drive mechanism which includes: a rocking beam having a rocker pivot, at least one cylinder and at least one piston. The piston is housed within a respective cylinder and is capable of substantially linearly reciprocating within the respective cylinder. Also, the drive mechanism includes at least one coupling assembly having a proximal end and a distal end. The linear motion of the piston is converted to rotary motion of the rocking beam. Also, a crankcase housing the rocking beam and housing a first portion of the coupling assembly is included. The machine also includes a working space housing the at least one cylinder, the at least one piston and a second portion of the coupling assembly. An airlock is included between the workspace and the crankcase and a seal is included for sealing the workspace from the airlock and crankcase. A burner and burner control system is also included for heating the machine and controlling ignition and combustion in the burner.

A Stirling cycle machine. The machine includes at least one rocking drive mechanism which includes: a rocking beam having a rocker pivot, at least one cylinder and at least one piston. The piston is housed within a respective cylinder and is capable of substantially linearly reciprocating within the respective cylinder. Also, the drive mechanism includes at least one coupling assembly having a proximal end and a distal end. The linear motion of the piston is converted to rotary motion of the rocking beam. Also, a crankcase housing the rocking beam and housing a first portion of the coupling assembly is included. The machine also includes a working space housing the at least one cylinder, the at least one piston and a second portion of the coupling assembly. An airlock is included between the workspace and the crankcase and a seal is included for sealing the workspace from the airlock and crankcase. A burner and burner control system is also included for heating the machine and controlling ignition and combustion in the burner.

A system for underwater inspection including an inspection crawler are provided. The inspection crawler includes a housing having first and second sides, a power source, a controller, an inspection tool, at least two driving wheels, and a moveable center of gravity. A method for traversing a weld joint with the inspection crawler having a moving mass is also provided. In the method, the crawler is parked proximate to the joint, and the mass is slid along a slide rail to the second end of the crawler distal to the joint. The first end of the crawler is then propelled over the joint and the mass is slid to the center of the crawler. A center portion of the crawler is then propelled over the joint and the mass is slid to the first end of the crawler. The second end of the crawler is then propelled over the joint.

A system for underwater inspection including an inspection crawler are provided. The inspection crawler includes a housing having first and second sides, a power source, a controller, an inspection tool, at least two driving wheels, and a moveable center of gravity. A method for traversing a weld joint with the inspection crawler having a moving mass is also provided. In the method, the crawler is parked proximate to the joint, and the mass is slid along a slide rail to the second end of the crawler distal to the joint. The first end of the crawler is then propelled over the joint and the mass is slid to the center of the crawler. A center portion of the crawler is then propelled over the joint and the mass is slid to the first end of the crawler. The second end of the crawler is then propelled over the joint.

A self-locking apparatus for a gear set permits forward-driving an input in clockwise or counterclockwise directions and substantially prevents an output from being driven in either or both of those directions. The device includes a gear set with planet gears arranged within a planet carrier within a fixed ring gear. Each of the planet gears is engaged with the planet carrier via a differentiating connector retained in an elongated slot in the planet carrier where it moves to the clockwise position when being forward driven in the clockwise direction and, when the planet carrier is back driven in the clockwise direction, the connector moves to the counter-clockwise position in the slot. This arrangement allows the gear set to be forward driven but not back driven. This differentiated action can engage/disengage with any form of unidirectional engage/disengage mechanism. The apparatus is useful in industrial applications requiring self-locking gear sets.