Bimco is devising its own efficiency methodology to help owners of older ships deal with the International Maritime Organization's carbon-reduction framework.

The shipowners' organisation has teamed up with the Royal Institution of Naval Architects (RINA) after identifying a need for more accurate reference speed calculations in cases where sea trial data is unavailable.

For ships built before 2013, the IMO is introducing the Energy Efficiency Existing Ship Index (EEXI).