She could not have picked a better couple of days to get some grid work done.
Fourth year surveying student Grace Cinque spent two days last week lapping up the sun, while working with the Apache 4 uncrewed vessel to work out the depths of three major water areas in Dunedin.
She was at the Steamer Basin on Wednesday and then the southern reservoir and Sullivans Dam on Thursday doing hydrographic surveys.
It is part of her fourth year honours research project on the use of uncrewed vessels.
Apache 4 has a single beam echo sounder on it, which sends a pulse sound down to the bed every 0.1 seconds.
How long it takes for the sound to come back determines the distance.
On the Steamer Basin it does grids of 5m which calculates depths across the entire area.
‘‘So we'll come up with some depths, we will clean out all of the bits that have clearly been measured wrong, because sometimes it will just pick up some noise from the surface,’’ she said.
‘‘Then we'll make a bit of a surface out of it and because I'm at the school of surveying I can compare it to some data we have previously for the area.’’
It took about three hours to survey the basin, but longer for the Southern Reservoir and Sullivans Dam.
The good weather over the two days helped her keep the vessel on an even keel, she said.
The maximum depth of the basin was 8m-10m with a tidal range of 1m-2m.
She would come back with another uncrewed vessel in a few weeks to carry out more surveying. The Whio is named after the endemic blue duck.
The two sets of data would then be collated to come up with an accurate survey of the beds.
The Apache 4 was borrowed from Global Survey in Dunedin and the Whio from Discovery Marine Ltd in Christchurch.
Miss Cinque, originally from Wellington, is in her final year of study and said her options were open.
‘‘We're very lucky to have heaps of options with surveying.
‘‘We can do the ocean stuff, we can do the land stuff, we're everywhere,’’ she said.
