UPGRADED TWO-STROKE SERIES FROM MAN

The company said that the engines will be ready for the newbuild market and its anticipated pick-up after 2020, “when the fuel oil situation is expected to be more clear, and the Energy Efficiency Design Index(EEDI) will require lower CO2 emissions”.

The new iteration of the G80 utilises the full Mark 10 design platform previously introduced with the G90ME-C10.5. The main result will be an advance in power density and efficiency. In the case of a seven-cylinder model, the weight reduction will be approximately 5%, and the specific fuel oil consumption(SFOC) will be lessened by 2g/kWh over the whole load range.

The reduced weight is attributable to the reduced cylinder distance enabled by the flexrod-type connecting rod, the flexible main bearing support, and the optimised cylinder frame. To cater for the increased maximum pressure, the G90ME-C10.5 incorporates the latest design of combustion chamber components adopted from the G95ME-C10.5, the most potent engine in MAN’s low-speed offering.

For a VLCC where a seven-cylinder G80ME-C10.5 has been nominated as the propulsion installation, and at a specified maximum continuous rating(SMCR) of 22,500kW, MAN calculates that the daily consumption at 100% load will be 86.3t, compared with 87.4t for the engine in its Mark 9 layout(G80ME-C9.5). Pre-supposing a US$500 per tonne price tag for 0.5% very low sulphur fuel oil(VLSFO), this would translate into a US$531 per day fuel cost saving.

Depending on load and tuning solution, the G60ME-C10.5 will have a reduced SFOC of between 2.6 and 3.6g/kWh. The design is largely similar to the existing G60ME-C9.5, with the same outline, footprint, cylinder distance, and height of structural parts, so as to minimise the necessary changes in production and for ship installation. However, the uprated combustion pressures necessitate a review of the material, structure, and dimensions of moving parts and bearings as well as of the combustion chamber elements.

For a 2,500TEU intra-regional container vessel, where a six-cylinder G60ME-C10.5 main engine has been specified at an MCR of 12,400kW, MAN indicates a 42.2t/day daily fuel oil consumption at 90% load, as opposed to 43t/day for the Mark 9 version. This would suggest a US$410 daily saving on the basis of 0.5% VLSFO priced at US$500/tonne.