The G-types have designs that follow the principles of the large-bore Mk-9 engine series that MAN Diesel & Turbo introduced in 2006. Their longer stroke reduces engine speed, paving the way for ship designs with unprecedented high-efficiency.
At the introduction of the G80ME-C9, Ole Grøne, Senior Vice President Low-Speed Sales and Promotions, MAN Diesel & Turbo, said: "MAN Diesel & Turbo always follows developments in the shipping market closely and we have kept a close eye on the trend for fuel optimization in recent years. As such, we have experienced great interest in the G-type engine during extensive consultation with industry partners and are currently working on a variety of projects with shipyards and major shipping lines. As a result, we have reached the conclusion that the introduction of the G-type engine program is both viable and timely."
Mr. Grøne adds: "The speed and power of these G-type engines have been carefully evaluated with a view to optimizing propulsion efficiency while, at the same time, facilitating their adoption by shipyards."
Rationale for G-type introduction
Tankers and bulk carriers have traditionally used MAN B&W S-type engines with their long stroke and low engine-speed as prime-movers, while larger container vessels have tended to use the shorter-stroke K-type with its higher engine speed.
Following efficiency optimization trends in the market, MAN Diesel & Turbo has also thoroughly evaluated the possibility of using even larger propellers and thereby engines with even lower speeds for the propulsion of tankers and bulk carriers. Larger container vessels are now increasingly being specified with S80ME-C9 and S90ME-C8/9 engines because of the opportunity they offer to employ larger propeller diameters; an S90ME-C9 engine will replace a corresponding K98 with the same cylinder count.
Such vessels may be compatible with propellers with larger diameters than current designs, and facilitate higher efficiencies following adaptation of the aft-hull design to accommodate a larger propeller. It is estimated that such new designs offer potential fuel-consumption savings of some 4-7 percent, and a similar reduction in CO2 emissions. At the same time, the engine itself can achieve a high thermal efficiency using the latest engine process parameters and design features.
Final drawings for the structure, moving parts and fuel equipment of the first G-type – the G80ME-C9 – are scheduled for delivery by mid-2011 with piping and gallery drawings scheduled to follow in the latter part of 2011, depending on order dates.
June 1, 2011