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savings and effi ciency of installing electrical cable versus hydraulic piping as the energy source. Marfex is now work- ing with many U.S. shipyards and design houses to help achieve those production cost savings in U.S. construction. The proposed IMO regulations and the capability to re- duce deck chatter during cargo operations on the ATB ap- plications are not new to Marfl ex. The issue was studied in Europe in October of 2013 when the Dutch company completed a survey of noise measurements on the MDPC- 200 deepwell pumps while operating in Rotterdam to assess compliance with IMO guidelines. Working areas on board affecting the crew, areas located 275 meters from the vessel ashore and underwater survey points were all collected. The variable frequency drives allow complete speed con- trol of the deck mounted electric motor driven deepwell pump. Sound levels were recorded during idle speeds, full discharge and stripping exercises. At all RPM levels the survey concluded that the noise limits were easily met. The underwater noise levels measured from the terminal jetty to the port side of the tanker while one or more of the Marfl ex pumps were operating also produced interesting results. The port geometry, resonance between the quays and the slope of the bottom profi le all affected the noise generated by the pumping system. We found the results PROPULSION Marfl ex Variable Frequency Drive Cargo pump. (Photo cour tesy of the Maritime Aquarium at Nor walk) November 2014 56 MN MN Nov14 Layout 50-65.indd 56 10/23/2014 10:39:31 AM
