In-situ radiance data collected from the underwater radiometers plays an important role in vicarious calibration, validation of the ocean colour products and can also be used for developing the bio-optical algorithms. The in-situ radiance will be influenced by many factors like the incidence angle orientation of the sensor and the local oceanographic conditions. This paper highlights the influence of the orientation/tilts of the sensor, in particular, the hyperspectral underwater radiometer on the in-situ radiance measurement. The in-situ data collected in the Hooghly Estuary near Diamond Harbour regions are used for the present study to assess the effect of tilt on surface radiance (Ls) and remote sensing reflectance (Rrs). The tilt angles from 0-30 degrees in the blue, green and red regions of the spectrum were considered which are mostly used for estimating the ocean colour or the geophysical parameters like chlorophyll concentration etc. This study shows that errors in surface radiance and the remote sensing reflectance increases with an increase in tilts. The average percentage error of <3% for the tilts 0-5 degree and 7.37 to 14% for the tilts 5-10 and the error percent increases to more than 50% beyond 15 degree tilt angles, which suggests that radiometric measurements up to 100 tilts can be used for retrieval of ocean color geophysical parameters in buoy mode for collecting the in-situ bio-optical parameters.