During tests in MARIN’s wave basins, it was observed that large-scale current patterns may develop under the influence of wave generation and absorption. The velocity of these currents is very low, so they generally do not influence the behaviour of models. However, for specific experiments at low speeds – wave added resistance tests with small models or current drag tests – a residual current may influence the results significantly. Figure 1: Seakeeping and Manoeuvring Basin.