Abstract: A riser sensor unit is used to sense engagement of a subsea riser tool with a riser coupling. The riser sensor unit includes a power supply configured to convert alternating current to direct current, an intrinsic safety barrier connected to the power supply, and a first sensor powered by the intrinsic safety barrier. The first sensor is attached to a sub of the subsea riser tool and is configured to generate a first signal upon detecting contact of a bottom surface of the sub with the riser coupling. The intrinsic safety barrier is configured to receive the first signal from the first sensor and transmit the first signal to a control system located remotely from the intrinsic safety barrier.

Abstract: Systems and methods for a riser coupling are disclosed. A riser sensor unit for sensing engagement of a riser tool with a riser coupling includes a first sensor attached to a sub of the riser tool. The first sensor is configured to generate a first signal upon detecting contact with the riser coupling, and an intrinsic safety barrier is configured to transmit the first signal to a control system.

Abstract: A mechanism to reduce load of a hydraulic cylinder having a body, a stem movable within the body, and a piston rod connected to the stem. The mechanism includes a mechanism body attached to the body and defining a recess, and a retainer attached to the mechanism adjacent the opening of the recess so that the retainer substantially fills the opening of the recess, and having an aperture that receives an end of the piston rod. The mechanism further includes a cap attached to the piston rod of the hydraulic cylinder within the recess, the cap having a diameter greater than the diameter of the aperture in the retainer, and a spring connected to the cap at a first end and to the retainer at a second end so that as the piston rod moves relative to the failsafe mechanism body, to reduce load transfer between the piston rod and the cylinder body.

Abstract: A mechanism to reduce load of a hydraulic cylinder having a body, a stem movable within the body, and a piston rod connected to the stem. The mechanism includes a mechanism body attached to the body and defining a recess, and a retainer attached to the mechanism adjacent the opening of the recess so that the retainer substantially fills the opening of the recess, and having an aperture that receives an end of the piston rod. The mechanism further includes a cap attached to the piston rod of the hydraulic cylinder within the recess, the cap having a diameter greater than the diameter of the aperture in the retainer, and a spring connected to the cap at a first end and to the retainer at a second end so that as the piston rod moves relative to the failsafe mechanism body, to reduce load transfer between the piston rod and the cylinder body.

Abstract: Systems and methods for a riser coupling are disclosed. A riser sensor unit for sensing engagement of a riser tool with a riser coupling includes a first sensor attached to a sub of the riser tool. The first sensor is configured to generate a first signal upon detecting contact with the riser coupling, and an intrinsic safety barrier is configured to transmit the first signal to a control system.