Hi I'm new here from Melbourne, I bought a splash drone fishing drone. It was ok never flew quite as nice as my old phantom 3 ever did. 

Anyway it run out of battery 350m out to sea and took a load of water and everything is toasted. It does turn on but won't arm. 

Im thinking of gutting it but motors and the drop mechanism and putting a custom drone internals 

Now I literally have no idea where to begin with this. All I need is 500m range and GPS return to home and a trigger for drop mech . I believe it's currently got 40amp ESC so something 40-50 would be fine.

Any recommendations or is their someone interested in doing this for cash?