MARIN develops unique Underwater Measurement System


UMS: MARIN’s special eye for underwater behaviour


MARIN decided to tackle the problems associated with measuring underwater motions by developing a new Underwater Motion Measurement System. Report outlines the UMS.


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Reinier Bergevoet & Edwin van de Bunt r.bergevoet@marin.nl


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or years, MARIN has been able to measure 6 Degree of Freedom (DoF) motions for floating structures using


Krypton (now Nikon), Rodymm DMM optical measurement systems. This system uses three cameras mounted on a beam which track synchronised active markers on the model. These systems can measure motions of structures with the active markers above the water surface.


Traditionally, motions of submerged struc- tures were determined using accelerometers or video recordings. Determining low-fre- quency motions from accelerometers is very inaccurate. Using video recordings to deter- mine the motions is very time-consuming and this technique can only be used to determine motions in the camera plane. Due to an increasing number of projects containing subsea structures, such as


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