Shipping companies focused on fuel efficiency and emissions reduction may be overlooking a hidden source of cost when operating in rough seas that ClassNK researchers say can quietly erode performance, waste fuel, and damage engine components. 

A new technical study from ClassNK’s research institute captures the way a persistent mismatch between commanded and actual main engine speeds - commonly referred to as a “speed gap” - can lead ships to burn significantly more fuel than necessary in heavy weather. The phenomenon, though well known to engineers in principle, has not previously been quantified or clearly connected to real-world fuel losses and maintenance implications.