Postponing mandatory maintenance using REDS

Aviso’s Engine Monitoring System REDS is a non-invasive continuous measurement instrument. It is designed to measure whether the engine is running in a balanced state by recognizing functional deviations.  

Using monitoring to postpone replacing the vibration dampers

REDS was installed on a Ro-Ro Ferry, sailing between Hoek van Holland and a U.K. port, as part of a ship owner's Energy Savings Program.

Aviso was asked by the ship owner to also monitor the functioning of the vibration dampers. These dampers were reaching the end of their life time (based on running hours) and should be replaced by new ones.

As docking time for the vessel was scheduled in a year from that moment, the owner wanted to know if the functioning of the dampers was still sufficient enough to postpone replacing the vibration dampers until that time.

Class regulation (Lloyds Register in this particular case) prohibits any further operations at sea when the damper exceeds its lifetime or when damper functionality is limited by damage or other root causes. Using REDS allowed the owner to continuously monitor the engine excited torsional vibrations.


Class agreed to postpone the mandatory replacement of vibration dampers

After officially informing Lloyds Register about the situation Class agreed to postpone the mandatory replacement of the present vibration dampers on board.

Class imposed the following terms and conditions:

  • the damper condition must be watched and monitored by REDS;
  • a 3-monthly report of REDS measurements must be handed over to Class;
  • use REDS as “permanent watch dog” for the remaining time at sea.

The vessel went on to complete its’ remaining operational time at sea under auspices of REDS. No further obstruction, delay or suspension occurred which caused and/or required expensive in-between measures to be taken.


We can conclude that the philosophy of “time dependent” and “class related” maintenance  on board of ocean going vessels, under certain circumstances, may be “subject to discuss”. The application of engine diagnostic monitoring systems (such as REDS)  help greatly in enabling “conditional” based maintenance.

More specifically, the cost saving as a result of postponing mentioned damper replacement far outweighed the investment in REDS.


Please click here to download Business Case REDS - postponing mandatory “class” related maintenance using REDS.pdf