On behalf of the Swedish Maritime Administration (SMA), Heinzmann has retrofitted the 40-year-old icebreaker Ymer with common-rail injection and a modern control, monitoring, and safety system. Heinzmann has also replaced the turbochargers on the five engines, each of which has a power output of 3.5 MW. In addition, the engine speed under partial load is no longer fixed, but variable at a lower level. During testing in field service, the overall fuel consumption was 11 % lower. Furthermore, visible smoke disappeared completely, the amount of lubrication oil used fell by 50 %, vibration levels dropped by 30 %, and the maintenance costs were significantly reduced.