Efficiency optimisation trends in the market
MAN Diesel & Turbo’s assessment of the two-stroke market has borne fruit with a number of Greek shipowners showing concrete interest in the company’s new, G-type, ultra-long-stroke engine program. Athens-based shipowner Thenamaris has placed
a surprise order for four 6G80ME-C9.2 engines to power 4 × 5,000-teu container vessels, to be built by Hyundai (HSHI) in South Korea. Specifications for the contract indicate a ship speed at NCR of 21.5 knots with a design draft of 12 m. Hull numbers S616 – S619 have already been assigned to the newbuildings with the first ship scheduled for delivery in August 2013.
MAN Diesel & Turbo reports that another, Greek shipping company is currently undertaking a technical evaluation on the feasibility of using the 6G80ME-C engine in a series of 4,800-teu container vessels to be built at Zhejiang Ouhua Shipbuilding Co., Ltd. in China.
MAN Diesel & Turbo said that it is also currently involved in several, active VLCC projects where the G80ME-C9.2 is the preferred engine choice. Indeed, this vessel type was originally the primary target behind the introduction of the G80ME-C9.2 engine. The shipping industry is currently debating whether or not VLCC lay-out speed should be reduced to 13 knots from the existing 15 to 15.5 knots, a scenario which the G80 is tailor-made to meet.
Ole Grøne – Senior Vice President Low-Speed Promotion & Sales – MAN Diesel & Turbo said: “We are delighted with the market response to the G-type. We viewed its introduction as both viable and timely and are pleased that the market has seen fit to back this up.”
The G-type program
The G-type programme was introduced to the market in October 2010 with the G80ME-C9 model. MAN Diesel & Turbo subsequently expanded the ultra-long-stroke programme in May 2011 with the addition of G70ME-C9, G60ME-C9 and G50ME-B9 models.
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, thereby paving the way for ship designs with unprecedented high-efficiency.
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 optimisation 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%, and a similar reduction in CO2 emissions. Simultaneously, the engine itself can achieve a high thermal efficiency using the latest engine process parameters and design features.
Source: Man Diesel & Turbo
