The operation of a ship at a lower speed than normal one in order to save fuel on ballast voyage or when fuel is expensive. Wärtsilä has introduced a new Upgrade Kit for Slow Steaming for RTA and RT-flex low-speed engines to improve the engine’s efficiency when running off it’s design point. The Upgrade Kit allows Wärtsilä low-speed marine engines to be operated continuously at any power in the range of 20% to 100%. This means that with the Upgrade Kit ships can sail continuously at sea speeds down to some 60% full speed.