The geographical and temporal distributions of worldwide ship drift velocities were plotted in order to see where and when the observations were made and to identify what appear to be major gaps in the data. Curiously, large areas of the North Atlantic, North Pacific, and South Pacific were found to be devoid of observations in some months during the years 1920--1934 when the number of yearly observations is large. An estimated 700,000 observations are missing. These would significantly enhance the usefulness of the data set if they could be found and added to it, especially in the Pacific where the data density is low. ¿ American Geophysical Union 1989