AIS Share is an app for Android that allows you to turn an Android device into an AIS receiver by using an RTL-SDR. AIS stands for Automatic Identification System and is used by ships to broadcast their GPS locations, to help avoid collisions and aid with rescues. An RTL-SDR with the right software can be used to receive and decode these signals, and plot ship positions on a map.
AIS Share is a dual channel decoder that outputs decoded NMEA messages via UDP, so that plotting software like OpenCPN can be used to display the ships on a map. The app costs about $2 and is available on the Google Play store, but there is a demo available that will work up until 1000 messages are received. You will need an RTL-SDR and a USB OTG cable to run the app.
Recently Christian, the author of the app received word from a user called Harmen who has successfully been using his AIS Share app on his sailboat. Harmen uses the app on an Android tablet which is enclosed in a waterproof box. For an antenna he uses a coax collinear.
In the future Christian writes that he’d like to update the app to support things like the ability to change more dongle settings like bandwidth/sample rate and add the possibility of using the internal phone/tablet GPS. He is also open to any community suggestions.
AIS Share Receiver on the sailboat in a waterproof case. 
The back of the Android Tablet, showing the RTL-SDR and the antenna connection.
La suite à lire sur le site de : RTL SDR Using AIS Share, OpenCPN and an RTL-SDR on a Sailboat