xqctide - marine chart viewer and tidal stream plotter
This program displays marine charts in QCT format and overlays the tidal streams as arrows whose size indicates the water speed. There is a date/time slider to display tidal streams throughout the day so you can find slack water for diving. Warning: the tide information is based on freely available harmonics and is not guaranteed. The charts are also not certified for navigation.
The program was originally written with Qt version 3.