This data repository houses the primary field data collected by Greer Jarrett during his doctoral research, 2020-2025. The datasets relate to the sailing trials and trial voyages conducted onboard Nordic clinker boats in various waters around Scandinavia, and form the foundation for several of his publications (see below). This repository houses two datasets: 1) The GPS tracks and log from the sailing trials and trial voyages. The GPS tracks are stored in 'Jarrett_GPS_tracks_all_sails.shp' (and accompanying files with the same name), while the log is stored as both a shapefile ('Jarrett_sailing_log.shp' and accompanying files of the same name) and as a spreadsheet ('Jarrett_sailing_log.dbf'). Please see 'Jarrett_field_data_metadata.txt' for more information on the shapefiles and spreadsheets. 2) Accompanying each sailing trial or trial voyage is a Word document describing the context, aims, and results of each experiment. Please see sails001-026_readme.txt. for more information on the accompanying Word (.docx) documents. For help with these data, do not hesitate to contact the author.