The SonTek CastAway is the world's first CTD that can instantly display profiles for temperature, (specific) conductivity, salinity, depth and the resulting sound velocity to a depth of 100m. Owing to its fast response time, the CastAway is designed to descend into the water column at a free fall rate of 1m/s.
Equipped with a built-in GPS, the SonTek CastAway records a coordinate position both at the beginning and at the end of the profile recording. Sound velocity and salinity are calculated internally without having to connect to a PC. The results are displayed on a built-in graphic display as soon as it is taken out of the water and the GPS position is determined.