Page 99: of Maritime Reporter Magazine (June 1998)

Table 1

Comparing Atlantic-class with SL-31-

Atlantic class SL-31

Length (o.a.) 949 ft. (289.5 m) 856 ft. (261 m)

Length (b.p.) 915 ft. (279 m) 814.6 ft. (248.5 m)

Beam 105.6 ft. (32.2) 105.6 ft. (32.2 m)

Depth 70.5 ft. (21.5 m) 70.5 ft. (21.5 m)

Draft, design 35 ft. (10.7 m) 32.8 ft. (10 m) (as Econships)

Draft, load line 38.4 ft. (11.7 m) 38.4 ft. (11.6 m)

Speed, design draft, kt. 19.1 21 (18 as Econships)

Speed, load line draft, kt 18 20.4

Power, kW 20,588 25,388

DWT 56,480 46,987

GT 57,075 47,667

Total container capacity 4,354 3,918

Deck containers 1,890 1,934

Hold containers 2,464 1,984

Reefer 146 146

Boosting the power of the ships would require building a new engine room and stern, with the result that three perfectly good stern sections less than 10 years old, whose only fault was that they were underpowered, would be wasted. So the idea came up to build new fore- bodies for the old sterns, and create six new ships from the three old ones. "We contacted many shipyards, and received many proposals regarding the costs of forebod- ies, aftbodies, and re-joining. We excited many yards to think creatively," says Mr. Vulovic.

One yard so inspired was the Blohm + Voss shipyard of Hamburg, Germany, which appeared with a striking alternative. The builder proposed to cut three hatches from the large ships, subcontract the building of a series of smaller, new ships, and insert the excised sections into the new vessels. The newbuilding part of the plan was determined to be commer- cially impractical, but the reconstruction remained attractive, especially as its delivery timetable was shorter than that of a newbuild- ing. "Along the way we determined that the big fast ship built from the Atlantic class would be too expensive to operate, because to reach 24 knots using the fairly blunt forebody of the

ECON design would require a 12-cylinder engine."

The story took another turn when newbuild- ing prices hit a momentary trough, and IHI appeared with an attractive newbuilding pro- posal. "After speaking with IHI we realized that we could reach 24 knots using a new ship with only a nine-cylinder engine, because its hull lines would be designed to minimize power requirements," adds Mr. Vulovic. "The new- build price was competitive with the cut-and- paste costs. That is how the ideas developed to modify the existing ships into 21-knot, 2,800-

TEU vessels, and to build the Champion class.

So the simultaneous challenge was met by shrinking three of the larger Atlantic class ships to create the new SL-31 class of 3,918-

TEU vessels for the European service, and con- tracting for a series of newbuildings, designat- ed the Champion class, for the Pacific route. "Because the Econships were so huge to start with, even after removing the midbody, the SL- 31s ended up as 3,900 — instead of 2,800-TEU ships, giving lots of spare capacity," says Mr.

Vulovic. Even so, market opportunities changed once more during the construction pro- jects, requiring SeaLand to shift strategy yet again.

The challenge came in the form of obliga- tions to a new joint venture with the Danish shipping giant, Maersk, for a new pendulum service the long way round from the U.S. west coast to the U.S. east coast, to be called the

Suez Express. The service involved 14-week trips, demanding 14 ships in all, seven from each partner. Being involved in an ongoing newbuilding project enabled Sea-Land to sup- ply ships to meet these needs.

So, over the years, Sea-Land exercised and augmented contract options and grew the

Champion class from an initial four ship series into a nine-vessel family. In the end, the deci- sion to "downsize" the larger ships, which proved to be the catalyst in committing to the design and construction of the Champion ships, proved a sound one. The conversion was a long

Table 2

Length (o.a.) 958.6 ft. (292.2 m)

Length (b.p.) 895.6 ft. (273 m)

Beam 105.6 ft. (32.2 m)

Depth 70 ft. (21.2 m)

Draft, design 38 ft. (11.5 m)

Draft, load line 42.6 ft. (13 m)

Speed, design draft, kt 24.4

Speed, load line draft, kt —

Power, kW 36,470

DWT 48,26

GT 49,985

Total container capacity 4,062

Deck containers 2,121

Hold containers 1,94

Reefer 350

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Cooperation a key to success

Blohm + Voss began by addressing the prob- lem of redesigning the ships' lines. The builder set about proving it could achieve an increase in speed without requiring a whole new fore- body. In the end, modifications resulted in what is nearly a three-knot boost in speed, when the new and old ships are compared at the same draft. The yard undertook a series of model tests at the HSVA model basin in Hamburg, confirming the results with hydrodynamic and computational aerodynamic calculations. These showed that modifications to the bow of the ves- sel could lead to a significant improvement in speed. Close contact between Sea-Land, the engine supplier (Sulzer), the propeller supplier (KaMeWa) and ABS resolved propulsion and vibration questions quickly. Likewise, coopera- tion between these suppliers and B+V began to yield results in the continuing speed-increase studies. Ultimately, the power savings achieved through a redesign of the lines, removal of the midbody, and the incorpora- tion of a more efficient propeller fell just short of the required goals, so a small booster engine was added. Reversing the com- mon idea of power take-off, to create a power booster, was yet another of this project's inven- tive solutions.

It was determined that, by using a complex electronic con- trol system and an electric motor driven by a diesel engine,

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