Experiments with a blue-green laser radar system were conducted off the coasts of Ireland and Scotland in June, 1999. The purpose of this test was to measure the effect of the water optical properties on the polarization state and decay rate of the lidar return signal. The lidar system, the K-meter Survey System (KSS), was configured to transmit linearly polarized light and to receive cross-polarized light in one channel and both polarization in the other channel. Several oceanographic ground truth instruments were used to measure the water optical properties, including transmission, absorption, backscatter coefficient, diffuse attenuation, temperature and salinity, as a function of depth. The KSS was mounted on the bow of one of the UK survey vessels, the HMS Roebuck, and the oceanographic instruments were deployed with a deck-mounted winch. The results presented in this paper were obtained both inside and outside of the continental shelf. Since these regions were characterized by different water optical properties, the sensitivity of the lidar return signal in terms of decay rate and polarization to different water clarities was determined.