Electromagnetic data recorded at a field trial in June 2001 in the Stockholm Archipelago has been analysed. Two different electromagnetic dipole transmitters were used together with three electromagnetic sensorsystems for measurements of low frequency electric fields in shallow water. The first transmitter, with low current, was towed at a depth of 2 m past the sensors. Measured electric fields from these tracks have been analysed in terms of detection. The other transmitter, with higher current, was mounted dose to the seabed and was used to perform an environment assessment experiment. This dataset has also been analysed in terms of localisation. Horizontally stratified models of the electromagnetic environment have been calibrated against the data and equivalent conductivities of sediments and bedrock have been found. These models of the environment have been used in the localisation studies. The performance of three different detectors (matched-field, non-coherent and quadrature) has been evaluated on this data. Because of the simple signature of the transmitter, classification was not interesting to perform on this dataset. Instead, classification was performed on simulated data.