Fugro Germany Marine mobilized the Moving Vessel Profiler System (MVP200) as part of the survey equipment aboard the Survey Vessel Fugro Discovery in order to meet the client’s requirement to perform a sound velocity cast at least every two hours. Working on behalf of the Norwegian Hydrographic Service on the Mareano 2017 Project, the Fugro Discovery surveyed an area of 3220 km2 in the Barents Sea. During 16 operational days 130 of 150 CTD Profiles were automatically taken using the MVP system in water depths up to 400 m.
The CTD Profiles were verified and applied instantly to the EM712 Multibeam Echosounder acquisition software (Kongsberg SIS). With an average survey speed of 9 knots, the MVP towfish equipped with an AML Micro CTD was constantly towed behind the vessel; casts were performed with a vessel speed between 4 and 8 knots (depending on the desired profile depth). The MVP System proved itself to be very reliable, robust and relatively easy to operate. The capability to perform CTD cast while the vessel is underway not only saves a lot of time and labour but contributes to increased Multibeam data quality and significantly increases daily and overall production. CTD casts are performed regularly or as soon as the environmental conditions change due to fluctuation of surface sound velocity for example; The CTD profiles are applied immediately without the need to stop data acquisition.
During the Mareano survey campaign, the Fugro Discovery worked in areas where drift ice was present. When surveying in vicinity to isolated ice bergs or drift ice, the sound velocity in the upper water column was changing rapidly and the MVP system was used advantageously to ensure that the Multibeam Echo Sounder was frequently updated with the correct sound velocity and absorption coefficients while the vessel was underway constantly acquiring bathymetric data.