Have not seen this referred to in any reporting and I wonder why not:

A shutdown valve (also referred to as SDV or emergency shutdown valve, ESV, ESD, or ESDV; or safety shutoff valve) is an actuated valve designed to stop the flow of a hazardous fluid upon the detection of a dangerous event. This provides protection against possible harm to people, equipment or the environment.

a 'dangerous event' underwater would be a drop in line pressure, which is quite straightforward to measure.

Have not seen this referred to in any reporting and I wonder why not:

A shutdown valve (also referred to as SDV or emergency shutdown valve, ESV, ESD, or ESDV; or safety shutoff valve) is an actuated valve designed to stop the flow of a hazardous fluid upon the detection of a dangerous event. This provides protection against possible harm to people, equipment or the environment.

a 'dangerous event' underwater would be a drop in line pressure, which is quite straightforward to measure.

Have not seen this referred to in any reporting and I wonder why not:

A shutdown valve (also referred to as SDV or emergency shutdown valve, ESV, ESD, or ESDV; or safety shutoff valve) is an actuated valve designed to stop the flow of a hazardous fluid upon the detection of a dangerous event. This provides protection against possible harm to people, equipment or the environment.