Open your app. I'm on iOS so it might differ slightly to android.
At the bottom where you have "Route" "Start" and "Menu". Select Menu.
You should now have a list that reads:
Click on whatever it is you are looking for. For example Route
You should now have a list of all your routes with the route
name on the left and a little "i" icon on the right.
If you click on the route name it takes you back to the map and shows your route. You don't want that. Instead click on the "i" icon. This is very fiddly and you have to get it dead on.
Once you click on the "i" icon you get a screen
showing you details of the route, length, times, fuel consumption
At the very top of the screen
on the left there is a "back" button, on the right there is a square with an arrow coming out of it. That is the export button.
Clicking the export button will then present a list of options for export. These will be different depending on your device.
Hope that helps. Sorry I couldn't easily show the process in pictures.
p.s I also just checked on an old version of the boating
HD app on Android and there isn't an export link, so make sure that your app is up to date.