Sailings is a free Android app by Navigational Algorithms that helps solve various navigation problems involving course, distance, difference of latitude, difference of longitude, and departure. The app plots the route between a departure and destination point on a Google map using Rhumb line (loxodromic) and Great Circle (orthodromic) sailings. It calculates the waypoints of the great circle route, and also saves the difference between Rhumb line and Great Circle route, nodes and vertices of the Great Circle. However, it is important to note that this app is not designed for live navigation, but rather as a useful calculator for navigation.

The user interface is simple and easy to use, with zoom buttons, map types (normal, terrain, and satellite), and GPS location. The app requires the "Location" permission to be allowed and once switched on, automatic location detection is possible. For more details, the app provides a help section. Overall, Sailings is a useful app for anyone interested in navigation and solving navigation problems.