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Seaspan Saver, a 10,000 TEU container vessel is setting new standards in container ship de-sign. MARIN and Marine De-sign and Research Institute of China(MARIC) developed the hull lines of this unique vessel, which has been entirely designed with a low operational cost pro- file in mind. Canadian owner Seaspan re- quested a hull form that facilitates very low fuel consumption in the operational speed range, but at the same time it had to be able to keep an acceptable top speed. This approach is in stark contrast to pre-vious ideas, which have focused on hav- ing the highest possible top speed. With the current slow steaming trend and up- coming EEDI regulations this new ap- proach is favorable. With the aid of extensive CFD calculations and close co- operation, a well-balanced container shipdesign was created. However, it was undoubtedly a chal- lenge to balance a low operational speed range and acceptable top speed, particu- larly whilst taking multiple operationaldraughts into account. By using fast po- tential flow calculations and even more accurate (but time consuming) RANS calculations, a very good hull was de- signed. MARIN used its experience of having optimized over 30 single screw container vessels with a length of more than 300 m, in combination with full-scale speed trials data from these very large container vessels at the normal bal- last trial draught and, even more impor- tantly, at design draught. After the optimization of the hull linesa large ship model was manufactured. For large container vessels up to 20,000 TEU, hull models up to 13 m in length are usedwith propeller diameters close to 300mm.This avoids scale effects as much as pos- sible. Following the initial model tests with a propeller from MARIN?s own stock ? which contains several thousand propellers ? a propeller was finally de- signed by Japan?s Nakashima and a twisted leading edge rudder design was made by the German company Becker Marine Systems. The final model tests showed that the propeller was highly ef- ficient. Cavitation was checked by high-speed video observations. EYE ON DESIGNContainership DesignSetting New Standards Patrick Hooijmansis project man-ager at the Ships department of MARIN, the Maritime Research Insti-tute Netherlands. Email: [email protected] 36Maritime Reporter & Engineering News MR#11 (34-41):MR Template 11/3/2012 9:18 AM Page 36