Subsea actuation sub-system

Abstract

A subsea actuation sub-system comprising a position indicator and a rotation-to-linear mechanism is disclosed. The rotation-to-linear mechanism being fixable to a subsea structure comprising a valve with a valve stem, and being connectable to the valve stem of the valve for moving the valve between an open position and a closed position, the rotation-to-linear mechanism comprising a shaft with an end for receiving rotational input from a separate retrievable motor actuator, the end being positioned within a cylindrical bucket, the bucket comprising a cylindrical opening in an axial direction of the bucket and a through opening, in a radial direction, in a side of the bucket, the shaft extending through a bottom of the bucket to the rotation-to-linear mechanism. The position indicator indicating the position of the output movement of the rotation-to-linear mechanism on the valve stem, the position indicator being arranged to interact with the shaft within the bucket.