Page 32: of Maritime Reporter Magazine (November 2014)

32 Maritime Reporter & Engineering News • NOVEMBER 2014

EYE ON DESIGN added resistance.

Following the calculations, model tests were carried out in the Seakeep- ing and Maneuvering Basin. The basin is 170 m long, 40 m wide and 5 m deep.

The model tests were performed using a free-sailing, self-propelled scaled model of the container vessel. It is worth not- ing that the only connections between the model and the carriage consisted of free-hanging wires for measurement and power relay. These did not restrict the model motions in any way.

Roll Behavior

The ? rst series of tests was dedicated to an extended characterization of the rolling behavior of the vessel in the most unfavorable wave conditions. Given the relatively long natural roll periods asso- ciated with most of the installed loading conditions in comparison with the range of wave periods, the most unfavourable wave conditions with respect to roll were observed in long waves originating from the stern quarter. The test series also in- cluded speci? c tests to assess the risk of parametric roll. Besides the roll motion, attention was given to the transverse and vertical accelerations generated by the ship motions (mainly roll) at the bridge or on the container lashing system.

The second test series provided a de- tailed assessment of the vessel’s opera- tional performance for several sailing scenarios. The investigation encom- passed the quanti? cation of ship motions and associated accelerations, the risk of green water at the bow, slamming at the bow-? are and stern and added resistance due to wind and waves. During the tests a wide array of wave conditions was considered, ranging from normal storm conditions to hurricane-like conditions.

The resulting estimates of the risk of green water at the bow and slamming allowed MARIN to validate certain de- sign choices, such as the breakwater or bow-? are angle. Additionally, the mea- surements of the thrust and torque de- livered by the propeller yielded a good estimate of the wave induced added re- sistance and associated speed loss. It is also worth mentioning that this project thrust MARIN into the spotlight when rather unusually, Maersk Line requested that a ? lm crew were present during the tests. This documentary, “Maersk Line’s

Triple-E – the World’s Largest Ship,” is currently on air on the Discovery Chan- nel and is de? nitely worth a look.

The Author

Bastien Abeil is Project Manager at the

Ships Department of MARIN, the Mari- time Research Institute Netherlands.

MARIN offers simulation, model testing, full-scale measurements and training programmes, to the shipbuilding and offshore industry and governments. e: [email protected]

Below are the FATIMA Calculation Results

MR #11 (26-33).indd 32 10/23/2014 11:23:52 AM