ActiveCaptain Locations works with ActiveCaptain and eBoatCards to show you where your boating friends are located. You'll need a free ActiveCaptain and eBoatCards account. Then as you exchange friend requests with other boats, you'll be able to track their location on one basemap.
Because eBoatCards supports DeLorme inReach and SPOT Messenger, the location information received from those devices will also be combined onto the basemap display. This gives you one place to find your boating friends.
There are a variety of basemaps supported including maps, satellite imagery, and NOAA raster charts.