In some aspects of the inventive
subject matter, there is provided a monitor for monitoring at least one operational condition of an
underwater mooring line, the monitor comprising an elongate main body, a protective shroud, at least one operational condition sensor for monitoring the, or each, operational condition, at least one acoustic
transmitter, and (in some instances) a source of electrical power for powering the operation of the sensor and
transmitter. The main body has at first and second ends respectively first and second
mooring line connections (each configured for connection to a respective
mooring line) and an intermediate portion. In use, the intermediate section is under tension between the first and second ends when the
mooring line is under load. The, or each, operational condition sensor is attached to the intermediate section, the sensor having a
signal output for providing a
signal regarding the sensed operational condition.