Description: To estimate the disturbing influence of a ship's hull and superstructure on measurements of wind speed, air temperature and humidity and surface water temperature, data taken from R.V. "Meteor" are compared with simultaneous measurements from a meteorological buoy. It is shown that almost no systematic errors occur in the measurement of water temperature while the wet bulb temperature is generally indicated to high by 0.1°C to 0.2°C. However, due to large heating of the ship's body during daytime, a systematic increase of dry-bulb temperature is observed which also leads to erroneous values of relative humidity. During nighttime, the errors in dry-bulb temperature remain small. Wind-speed measurements, in particular, are critical from board a ship. The "Meteor" data show that the ship's values are systematically smaller than the measurements at the buoy, the difference increases with increasing wind speed. Although WARSH et al. (1972) found the same behaviour with R. V. "Discoverer", the result cannot be generalized, and similar investigation are recommended for any ship the data of which will be used for more extended evaluations. The errors are examined concerning their influence on the computation of turbulent heat fluxes from the bulk-aerodynamic equation. The result shows that, even if the diurnal march of dry-bulb temperature is corrected, the fluxes are still erroneous due to the wind-speed error. The conclusion, therefore, is that data taken from a ship are in general inappropriate for the more detailed investigation of surface-energy fluxes, unless a good correction function for all the parameters involved is known.