These data sets are the first sea tests of a custom turbidity sensor for the Sonic Kayak project https://fo.am/activities/kayaks/ Two tests were carried out - one in shallow water with mud swirled around to get an idea of the range, the second being left in the flow of a river (attached to a pontoon) to determine overall stability. The values represent brightness (higher as more light) as voltage across a light dependent resistor applied to a 12bit Arduino analogue to digital converter. The weather was a mix of overcast and bright sunlight.