I think it is much better to keep your sonar log files relatively short - perhaps 100-200MB or so. A few reasons for this: Files occasionally do get corrupted when recording (rarely, but it happens), so multiple, shorter files helps protect against losing data this way. Smaller files are better handled in ReefMaster, since data for the entire file needs to be loaded for sidescan viewing. It uses less memory, and is quicker, to load and view smaller files. Files can still be combined as required to create mosaics.