Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America.
Maersk North America, Charlotte, North Carolina, United States of America.
PLoS One. 2023 Mar 16;18(3):e0282677. doi: 10.1371/journal.pone.0282677. eCollection 2023.
The container shipping line Maersk undertook a Radical Retrofit to improve the energy efficiency of twelve sister container ships. Noise reduction, identified as a potential added benefit of the retrofitting effort, was investigated in this study. A passive acoustic recording dataset from the Santa Barbara Channel off Southern California was used to compile over 100 opportunistic vessel transits of the twelve G-Class container ships, pre- and post-retrofit. Post-retrofit, the G-Class vessels' capacity was increased from ~9,000 twenty-foot equivalent units (TEUs) to ~11,000 TEUs, which required a draft increase of the vessel by 1.5 m on average. The increased vessel draft resulted in higher radiated noise levels (<2 dB) in the mid- and high-frequency bands. Accounting for the Lloyd's mirror (dipole source) effect, the monopole source levels of the post-retrofit ships were found to be significantly lower (>5 dB) than the pre-retrofit ships in the low-frequency band and the reduction was greatest at low speed. Although multiple design changes occurred during retrofitting, the reduction in the low-frequency band most likely results from a reduction in cavitation due to changes in propeller and bow design.
集装箱航运公司马士基（Maersk）进行了激进的改装，以提高十二艘姊妹集装箱船的能源效率。本研究调查了改装工作中确定的潜在附加好处之一，即降噪。在本研究中，使用加利福尼亚州南部圣巴巴拉海峡的被动声学记录数据集，对十二艘 G 级集装箱船进行了 100 多次改装前后的偶然船只过境记录。改装后，G 级船舶的运力从9000 个标准箱（TEU）增加到11000TEU，这需要船舶平均增加 1.5 米的吃水。增加的船舶吃水导致中高频带的辐射噪声水平升高（<2 分贝）。考虑到劳埃德镜（偶极子源）效应，发现改装后的船舶的单极子源级在低频带中明显低于改装前的船舶（>5 分贝），在低速时降幅最大。尽管在改装过程中发生了多种设计变更，但低频带的降低很可能是由于螺旋桨和船首设计的变化导致空化减少所致。
