Abstract: A method for monitoring the operation of underwater-located equipment is provided. The method comprises: providing a sensor, the sensor comprising at least one of an acoustic sensor and an accelerometer, locating the sensor proximate the equipment to enable detection by the sensor of acoustic and/or acceleration components produced by the operation of the equipment, and producing electrical output signals in dependence on the detected components.

Abstract: A system for controlling production shut down of an underwater fluid production well, the well having a sensor for producing an output signal indicative of the state of the well and a valve which is actuable to shut down production activity of the well, comprises means for receiving the output signal; and a processor for processing the received signal to determine if a shut down is required and outputting a shut down signal to the valve; wherein the receiving means and processor are located at the well.