Full documentation and screenshots legend here:
Boatspeed consists of several components:
Sailing: provides a large display of your current speed and heading.
Navigation: lets you create and follow routes on the map of openseamap.
Tracking: records your trip, shows the track on the map and lets you export your data to gps, csv and jpg.
Regatta: provides a regatta start countdown.
Anchor alert lets you sleep peacefully :-)