Scope of Measurement of REDS

The shortest possible explanation of the scope of measurement of REDS can best be illustrated by explaining how REDS measures.

Engine Imbalances

REDS determines imbalances of piston engines by high resolution measurement of the dynamic rotational angular velocity of the crankshaft. Or in other words, torsional vibrations or accelerations and decelerations of the flywheel.
Imbalances are caused by both the thermodynamic processes in the engine, expansion and compression of gases, and (clearances of) moving parts like, for example, bearings.

REDS scherm met uitleg.JPG

Thermal Health (TH) & Mechanical Health (MH)

In the order described above, these imbalances are shown as Thermal Health and Mechanical Health on the system’s dashboard.

TH and MH values are shown on dials. Development of TH and MH values over time are shown in a graph together with the RPM. In REDS, a trend of increasing measurement values indicates a deterioration of the engine’s condition and performance, under comparable conditions. Increased imbalance results in increased fuel consumption, more wear and tear and thus higher maintenance costs.

Therefore continuous measurement of imbalances are extremely useful.



An engine failure can be detected at an early stage of development. Nevertheless, the majority of vessels, including very modern ones, operate engines that are significantly out of balance and the crew is not aware of this.

uitleg MH & TH.JPG

Trouble Shooting

For trouble shooting the user needs to investigate the engine further, supported by combining available information, such as:

  • further data provided by REDS,
  • other measurement values - such as exhaust gas temperatures, and,
  • the user’s own experience.


Data from other sensors can be input into the Aviso platform, which can be viewed on a customized dashboard.

It is important to distinguish imbalances during high engine load and low load. Many diesel engines show significant imbalance during low load and idling due to the behavior of the regulator and/or deviating injector characteristics.


Priority, however, needs to go to imbalance during high load over a longer period of time and during normal operation, for example during transit / cruising speed. Short term higher values, for example, during rapid RPM change whilst maneuvering is of lesser importance.

uitleg indicatoren.JPG