Case Study Optimization

Optimization of DSME's 14,000 TEU Container Vessel (MSC Danit)

With a capacity of 14,000 TEUs, an overall length of 365.5 meters and a deadweight of 165,517 metric tons, the MSC Danit is the world's largest container vessel. Finished by Korean shipyard Daewoo Shipbuilding & Marine Engineering (DSME) at the beginning of March 2009, it was the most discussed ship in 2008—and the most interesting. Unmet in capacity, size and speed, it is stunning in regard to its performance. DSME used the FRIENDSHIP-Framework for the variation and optimization of proven parent ships in order to arrive at maximum performance and efficiency. The final hull displayed less than 50 percent in wave resistance in comparison to the baseline! In addition, the optimization within the FRIENDSHIP-Framework had a favorable effect on the propulsion performance.

How was the optimization undertaken? The design conditions for the carrier were:

• L_OA of almost 380 m
• LPP around 360 m
• Breadth just below 52 m
• Design draft of 14 m
• Guaranteed speed of 24 knots
• Fn approx. 0.207
• 90% MCR with 15% sea margin at a scantling draught of 15.5 m

DSME  approached design and optimization of the carrier in two phases:

Phase 1 comprised

1. Selection of two proven parent ships with high nose type bulbs as starting point
2. Scaling to principal dimensions
3. CFD simulations for re-combinations of various fore and aftbodies
4. Choosing most promising candidate as baseline for parameter study
   

After selection of the study candidate, the following steps were undertaken in phase 2:

1. Investigation of a series of variants through parametric modeling and CFD
2. Identification of the influence of individual form parameters
3. Selection of the best hull form
4. Model testing at HSVA (Hamburg ship model basin)

In a systematic parameter study, the parent ships were varied by swinging the baseline's sections using the Generalized Lackenby approach of the FRIENDSHIP-Framework. With the Generalized Lackenby approach, the region of influence on the hull shape can be selected flexibly and, too, the slopes of the shift functions can be defined freely at either ends. Through this, variations may start well forward of the bossing and may end just aft of the forward perendicular. With zero slopes at the beginning and at the end, transitions become very smooth. A series of variants was produced and numerically simulated for wave resistance. Here, SHIPFLOW, the advanced CFD code of FRIENDSHIP SYSTEMS' cooperation partner FLOWTECH, was applied.
Variants indicated a beneficial modification of the parallel length of the mid-body from 5 percent to 15 percent LPP. Change to the sectional area curve (SAC) as available with the Generalized Lackenby was applied in steps of 5° from minus 25° to 25°. Through the increase of the parallel mid-body, the wave resistance coefficient could be reduced by up to 8 percent. A further tangible improvement was achieved through adjusted volume distribution at the forward perpendicular.
The hullform finally chosen for model testing featured a straight type and rather steep SAC with sharp angles at entrance and run and a comparatively long parallel mid-body. The design waterline displayed a small entrance angle and a relatively pronounced shoulder between stations 12 and 16.

Based on the results of the optimization within the FRIENDSHIP-Framework, a model of the optimized ship was tested in the towing tank at HSVA in Hamburg, Germany (see Fig. 2).

[Fig. 2] Model test for new hull form (photo courtesy of HSVA)

In relation to the baseline the final hull displayed a wave resistance minimized by more than 50 percent (different wave patterns are shown in Fig. 1) and, additionally, a positive effect on the propulsion performance. The wave patterns seen in the numerical simulations and too in the model tests were found favorable and stable. Reduced wave resistance and high robustness of the vessel guarantee maximum efficiency and durability (see Fig. 3).

In brief, the optimization within the FRIENDSHIP-Framework achieved:

• Reduction in wave resistance by more than 50 percent
• Modification of the mid-body
• Adjusted volume distribution at forward perpendicular
• Better propulsion
• Generation of stable wave patterns
• Higher robustness of the vessel
• Optimal trim

This led to an adjusted final hull form of 51.2 meters beam, 365.5 meters length and 16 meters draft.

[Fig. 3] Comparison to other carriers on the basis of HSVA's database

1. Increased speed performance
2. Increased automation
3. Speed up in optimization

The optimization of the ship hull has a lasting and very positive effect on the fuel consumption. With an optimized hull—and pushed by its 72,240 kW engine—the MSC Danit makes the most of every ton of fuel.

With its final properties as displayed above, the 14,000 TEU vessel has set standards for speed, shape and stability in its class of megaboxers. The position of the superstructures in the midship, the engine room located in the aft and the funnel position are very innovative and give high stability and optimal trim at maximum ship load.
All technical and building properties put aside, the MSC Danit is a real beauty.

[Fig. 4] MSC Danit first time at sea (courtesy of DSME)

Further information is provided in the paper "DSME sharpens edge for 14,000 TEU carrier" published by The Naval Architect  in the 2008 edition on "Design and Construction of Containerships", available on this website.

If you wish to get more details on the optimization or to get in touch with Lee Yeon-Seung and Choi Young-Bok of DSME's Hydrodynamic R & D team, please contact Mr. Stefan Harries.

[Fig. 5] MSC Danit frontal (courtesy of DSME)

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