DNV

EPL and ShaPoLi

The overridable engine power limitation (EPL) and the overridable shaft power limitation (ShaPoLi) were introduced by the IMO with MEPC.335(76), giving a clear definition of the technical solutions:

The EPL restricts the propulsion power directly at the main engine with a limitation of the maximum available fuel amount per injection. This can be realized with a mechanical blockage of the fuel rack or by a software limitation of the fuel index. Alternatively, software solutions can restrict the engine power instead of the fuel index.

The ShaPoLi measures the shaft power and provides the current value to the engine automation for a comparison with the limit value, to reduce the fuel index or propeller pitch in case the engine setting exceeds the power limit value. Alternatively, the shaft power can be displayed on the bridge and an alarm is given whenever the limit value is exceeded. The latter is the most popular version of ShaPoLi arrangements and is described in MEPC.390(81), an amendment to the MEPC.335(76).

https://www.dnv.com/news/propulsion-power-limitation-eexi-documentation-requirements/