A winch assembly comprising a support structure, a drum revolving about an axis; a cable wound around the drum; an actuator assembly coupled to the drum to wind or unwind the cable and configured to receive a first control signal, indicative of a desired pressure of a pump of the actuator assembly, and/or a second control signal, indicative of a desired displacement of the pump; and a winch control device coupled to the actuator assembly to control the winding and unwinding of the cable and configured to determine the first control signal and/or the second control signal according to a measured speed of travel signal indicating the measured speed of travel of the tracked vehicle, a measured pulling force signal indicating the pulling force measured on the winch assembly, and one or more signals selected from the following group of signals: cable speed signal, wound cable length signal, desired pulling force signal set manually by an operator, signal from the measured angle of the arm of the winch assembly with respect to a direction of travel, and measured pressure signal indicative of a pressure measured in a high pressure branch of the hydraulic circuit of the actuator assembly.

A winch assembly comprising a support structure, a drum revolving about an axis; a cable wound around the drum; an actuator assembly coupled to the drum to wind or unwind the cable and configured to receive a first control signal, indicative of a desired pressure of a pump of the actuator assembly, and/or a second control signal, indicative of a desired displacement of the pump; and a winch control device coupled to the actuator assembly to control the winding and unwinding of the cable and configured to determine the first control signal and/or the second control signal according to a measured speed of travel signal indicating the measured speed of travel of the tracked vehicle, a measured pulling force signal indicating the pulling force measured on the winch assembly, and one or more signals selected from the following group of signals: cable speed signal, wound cable length signal, desired pulling force signal set manually by an operator, signal from the measured angle of the arm of the winch assembly with respect to a direction of travel, and measured pressure signal indicative of a pressure measured in a high pressure branch of the hydraulic circuit of the actuator assembly.

A method for mitigating the effects of cable wear in an active heave compensated hoisting system of an offshore vessel in a locked to bottom mode of operation is disclosed. The method comprises supporting an upper end of a string which is connected to a subsea well from a travelling block of the hoisting system, wherein the travelling block is suspended from a crown block via a cable. The method further comprises operating an active heave compensation system to control a drawworks of the hoisting system to pay in and out the cable to compensate for motion of the offshore vessel and maintain a target overpull in the string. The method further comprises adjusting a ballast system of the offshore vessel to vary the draft of the vessel, and controlling the drawworks in accordance with the variation in the draft of the vessel to cause a length of cable to slip through the hoisting system and maintain the target overpull in the string.

A method according to certain embodiments generally involves operating a system including an unmanned aerial vehicle (UAV) and a base station. The base station includes a nest including an upper opening having an upper opening diameter and a lower opening having a lower opening diameter less than the upper opening diameter. The lower opening is accessible from within the base station. The method generally includes landing the UAV within the nest such that a portion of the UAV is accessible via the lower opening, releasably attaching a load to the UAV, and operating the UAV to deliver the load to a destination.

A method according to certain embodiments generally involves operating a system including an unmanned aerial vehicle (UAV) and a base station. The base station includes a nest including an upper opening having an upper opening diameter and a lower opening having a lower opening diameter less than the upper opening diameter. The lower opening is accessible from within the base station. The method generally includes landing the UAV within the nest such that a portion of the UAV is accessible via the lower opening, releasably attaching a load to the UAV, and operating the UAV to deliver the load to a destination.

A payload coupling apparatus is provided that includes a housing. The housing is adapted for attachment to a first end of a tether. The apparatus further includes a slot extending downwardly from an outer surface of the housing towards a center of the housing thereby forming a lower lip on the housing beneath the slot. The slot is adapted to receive a handle of a payload. The apparatus further includes a sensor configured to detect touchdown of the payload and a transmitter configured to send a touchdown confirmation signal to an unmanned aerial vehicle (UAV) based on a touchdown detection by the sensor.

A power winch with changeable connection position includes a first connection line and an induction line connected between a power source and an electric control box, which are connected to a second connection line for grounding the electric control box, and a third connection line is connected to the power source for grounding. These lines are connected to the exterior of the electric control box and the power source to facilitate a quick detachment from the electric control box and the power source.

An unmanned aerial vehicle according to certain embodiments generally includes a chassis, a power supply mounted to the chassis, a control system operable to receive power from the power supply, at least one rotor operable to generate lift under control of the control system, a line having one end coupled to the chassis and an opposite free end, wherein the free end is positioned below the chassis, and a severing mechanism operable to sever the line under control of the control system.

An unmanned aerial vehicle according to certain embodiments generally includes a chassis, a power supply mounted to the chassis, a control system operable to receive power from the power supply, at least one rotor operable to generate lift under control of the control system, a line having one end coupled to the chassis and an opposite free end, wherein the free end is positioned below the chassis, and a severing mechanism operable to sever the line under control of the control system.

A method according to certain embodiments generally involves operating a system including an unmanned aerial vehicle (UAV) and a base station. The base station includes a nest including an upper opening having an upper opening diameter and a lower opening having a lower opening diameter less than the upper opening diameter. The lower opening is accessible from within the base station. The method generally includes landing the UAV within the nest such that a portion of the UAV is accessible via the lower opening, releasably attaching a load to the UAV, and operating the UAV to deliver the load to a destination.