Page 44: of Maritime Reporter Magazine (March 2002)

owners turned almost exclusively to diesel. Only in terms of the large express liner could steam be classed as more eco- nomic than diesel in the late 1930s.

In the years preceding WWII, most diesels installed in the

U.S. were direct drive reversing engines. Rapid expansion of demand for engines in the 50s and 60s led to a wide range of engines for propulsion varied from about 100 to about 5,000 bhp. Single reduction gear sets fitted with control- lable reversing propellers or reversing reduction gears were available in a variety of sizes and the installation and capi- tal costs of this arrangement were considerably lower than those of a steam plant.

Postwar diesel engine development proceeded in two almost diametrically opposed directions. For naval applica- tions, engines were small, high-speed, and light-weight. Yet in merchant ships the trend was toward large, slow-speed engines of high power and high efficiency that burned cost- ly fuels and maintained lower rpm to match lower propeller speeds. Diesel propulsion became more and more dominant in merchant ships even before the oil shortage in the 1970s overshadowed all other considerations in selecting machin- ery.

Marine Power Plants Today

In the late 80s and early 90s engineers began to recognize the attributes of gas turbine power that would make it acceptable for commercial use. To preserve the maximum amount of ship space for generating revenue, owners sought compact and lightweight power solutions. The first main commercial use for gas turbines was in fast ferries. Today, space concerns and environmental interests have led some cruise lines to take another look at gas turbine technology.

Citing a goal to produce "the most environmentally sensi- tive cruise ships in the world," Demetrios Kaparis broke new ground in 2000 with his decision to implement gas tur- bine power — a technology he considers to be the "future of marine power plants" — on Celebrity's Millennium. While fuel cr ' are greater because of the use of distillates, some cruise lines have discovered an economic advantage to gas turbine-based plants, according to Dave Luck, manager of marine applications and ship integration at GE. "Having more cabins in the ship can more than offset the higher fuel cost." said Luck. In addition, pending environmental regu- lations and increased concern about exhaust emissions in some of the regions cruise ships serve have further influ- enced the decision to choose gas turbines.

Increasing environmental concern has also garnered new attention to earlier experiments with liquified natural gas (LNG) carriers. By next year, if all goes according to plan.

Statoil will become the first operator on the Norwegian con- tinental shelf to feature LNG powered propulsion on its ves- sels. While the construction cost of each vessel increased by $6 million, the company chose LNG technology because it would greatly reduce emissions.

Sources: Steam at Sea, by Dennis Griffiths, Conway Mar- itime Press, 1997.

Smoke Ash and Steam: Steam Engines on the West Coast of North America, by Robin E. Slieret. Western Isle &

Cruise Drive Co. Ltd. 1997.

A Half Century of Maritime Technology 1943-1993, Ed. by Harry Benford and William A. Fox: Powering Section written by David O'Neil, the Society of Naval Architects and Marine Engineers, 1993.

A freelance journalist for Newsweek, Rolling Stone, and

Newsday, among other publications, Jessica DuLong is also assistant chief engineer on retired New York City fire - boat John J. Harvex. 44 Circle 287 on Reader Service Card or visit www.maritimereporterinfo.com

Gas Turbines Continue

Making Commercial Inroads

GE Marine Engines has been supplying integrated propulsion systems for a variety of commercial and military marine cus- tomers for more than 25 years. GE's com- plete line of aeroderivative gas turbines includes the LM500 (6,000 hp). LM1600 (20.000 hp), the LM2500 (33,600 hp), the

LM2500+ (40,500 hp) and the LM6000 (57,330 hp).

For instance, the first gas turbine-pow- ered fast ferry in Greece entered service in the summer of 2001. This Corsaire 14000- class monohull is powered by two GE

LM2500+ gas turbines in a combined diesel and gas turbine (CODAG) arrange- ment with two diesel engines.

The ship was built for operator Maritime

Company of Levos (NEL), Piraeus,

Greece, by Alstom Leroux Naval Shipyard in France.

The MDV 3000 program uses GE

LM2500 gas turbines on the Capricorn,

Scorpio, Aries and Taurus fast ferries.

These vessels operate in the summer months on the Civitavecchia-to-Sardinia

Island and Genoa-to-Sardinia Island routes in Italy.

The MDV 3000 are the world's largest fast ferries, and were built by Fincantieri,

Genoa. Italy for Tirrenia Lines. With total power output at more than 70 MW per ves- sel. the ferries are capable of reaching speeds in excess of 40 knots, and can carry 1,800 passengers and 460 vehicles.

Another operation has 12 LM aeroderiv- ative gas turbines in service on the three

Highspeed Sea Service (HSS) fast ferries — Stena Explorer, Stena Voyager and

Stena Discovery — since April 1996, July 1996 and June 1997, respectively. Owner

Stena Line AB. Gothenburg, Sweden, oper- ates the HSS ferries on the Irish Sea between the United Kingdom and The

Netherlands.

Each semi-swath fast ferry has two

LM 1600 and two LM2500 gas turbines in a

COmbined Gas and Gas turbine (COGAG) configuration. Combined the LM1600 and

LM2500 gas turbines aboard the three ves- sels have logged more than 165,800 hours in service.

Built by Finnyards in Rauma, Finland, the HSS fast ferries measure 413 x 131 ft. (126 x 40 m). Each vessel can achieve speeds of more than 40 knots and have the capacity for 1,500 passengers, 375 cars, or 50 trucks and 100 cars. For instance, GE recently announced that Cunard Line selected two LM2500+ gas turbines in a

CODAG configuration with four diesels for

Queen Mary 2. This transatlantic liner will be the world's largest passenger vessel upon completion in 2003.

To date. GE has supplied COGES propul- sion systems for Celebrity Cruises' three

Millennium class vessels, as well as Royal

Caribbean's Radiance of the Seas.

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Maritime Reporter & Engineering News

ASNE

Day 2002

Annual

Meeting and

Symposium

Transformational Technologies for Future Naval Systems

ASNE Day 2002 will explore a number of ship concepts and mission systems technologies that are being proposed to help our naval forces to meet future war fighting needs, such as: • Advanced ship and craft designs that promise high speed, large payload and good seakeeping characteristics • Advanced propulsion and power concepts • Advanced mission systems compatible with electric ship concepts (703) 836-6727 www.navalengineers.org

For insight into these and other exciting naval technologies, don't miss ASNE Day 2002,

April 29 & 30

Hyatt Regency Crystal City Hotel in Arlington, Virginia.