Marine diesel engines have long served as the beating heart of global seaborne trade. From 20,000-TEU box-ships that synchronize their arrival to within minutes of port schedules, to the compact but rugged medium-speed units that keep fishing fleets alive in the North Pacific, diesel power remains unrivalled in its combination of energy density, operational flexibility and economic predictability. Yet the environment in which these engines operate is changing at a pace unprecedented since the shift from coal to oil a century ago. Carbon intensity targets, zero-sulphur fuels, remote monitoring...