UnderwaySV for Norwegian NHS

The Norwegian Hydrographic Service (NHS) recently conducted the first-ever multibeam survey using the UnderwaySV sound velocity profiler to provide critical sound speed data. The partnership of the Oceanscience Group's Underway deployment system developed for the UnderwayCTD, and the Valeport ‘free-fall' RapidSV probe has generated the first compact Underway sound speed profiler. Released early in 2011, the NHS took delivery of the first UnderwaySV system off the production line.

According to Dag Hodnesdal of NHS, "Taking a sound velocity profile is much easier now than it used to be. Since we can take a profile while underway we save a lot of time, making us more efficient". NHS hydrographers were among the first to hear about the UnderwaySV, Dag explains "Until this year we have been using a CTD profiler for generating sound speed profiles down to 400 metres. This is a very time-consuming operation because the vessel has to stop each time. Since we are only operating in such deep water areas 2 months a year it has been impossible to justify a large and expensive deep water profiler. At the Hydro2010 conference we saw a presentation about the UnderwaySV, which to us seemed to be a very cost-effective solution ".

The NHS are tasked with completing the bathymetry of all coastal areas in Norway, including the fjords and bays, representing 25,000 kilometres of coastline. This mapping effort requires increasing vessel productivity.

The Hydrograf crew is also grateful for the UnderwaySV for quite unexpected reasons, Dag explains: "The crew off-shift is no longer disturbed while taking a profile. Prior to getting the UnderwaySV, we had to stop the vessel, position it against wind and current and then take a profile. This made a lot of irregular noise from the propeller and the main engine, disturbing the crew."