INSEAN has a free-surface large Circulating Water Channel that can be depressurised. This facility is used for such tests as: cavitation observation tests, cavitation inception measurements, and performance tests with propellers in wake field behind the model; hull pressure fluctuation measurements; propeller noise and radiated noise measurements; flow pattern tests; measurements of hydrodynamic forces and moments on rudders, foils, etc. The test section is 10 m long, 3.6 m wide with a depth of 2.2 m. The maximum water speed is 5 m/s. The pressure in the test section can be reduced up to a minimum of 30 mbar. A 3-D Laser-Doppler Velocimeter (LDV) is used for the measurement of flow velocity components during 3-D wake surveys.