“A PLC is an industrial controller that continuously monitors the state of input devices and makes decisions based upon a custom program to control the state of output devices. Without a [functioning] PLC, the system cannot operate,” explains Con van Twillert, Heinen & Hopman’s senior cooling engineer. The systems in question pertain to the monitoring of on board HVAC plants, including the chiller(s) and/or cooling plants.
Yachts built before 2007 may contain PLC systems that are no longer in production and may require replacement parts or calibrations that are equally unattainable in system malfunction scenarios.
The risk of system failure may be significant. “Consequences may be that the chiller, air handling unit, or provision cooling systems will be out of operation until the [unattainable] replacement parts are installed,” continues van Twillert. If such a scenario materialises during a private cruise, or more pressingly, during a charter, the ramifications could be severe.
Parties responsible for the running of yachts built pre-2007 are advised to have their PLC systems checked and implement any measures necessary to avoid system failure.