This app includes the same functionality as our free Marine Barometer app available in the App Store, with several valuable features added. You can review the basic features of the design by installing and becoming familiar with the free Marine Barometer app. The new features in this Marine Barograph app include: automatic storage of atmospheric pressure, with time and date, GPS position, course over ground (COG) and speed over ground (SOG). The pressure data can be graphed (pressure versus time) over several time intervals from 30 min on up to 16 days. The graphs can be pinch zoomed for more detail or double tapped to expand both scales. Use Reset View button to undo changes. Tap the graph at any point to read time and pressure at that point. Large digital displays can be viewed from a distance, including prominent pressure trend arrows (visible when data one hour old is available). On the three-hour display, the official pressure tendency is computed and displayed, and the shape of the curve in view can be used to determine the pressure tendency characteristic code used in official ship reports. Also new are options for pressure display (sea level or station), precision, and latitude and longitude formats. The stored data can be viewed from within the app or exported and shared according to time range of the storage files. The stored data are effectively a log of the voyage with navigation information as well as the pressure data. Besides the pressure data, your track of GPS positions can also be exported to view in a navigation program or Google Earth. This app can be used to convert a second or older iPhone (iPhone 6 or newer) not otherwise in use into a valuable stand-alone electronic barograph and voyage data logger. Just load the app and plug it in for continual viewing. The full help file with details of operation and tips on the use of atmospheric pressure in navigation is included in the app. This file can be viewed online at https://www.starpath.com/marinebarograph along with videos showing how to use the app.