It doesn't seem to matter if the turtles on their spawn beach or the beach they were born on. I feed 2 turtles and the pregnant one (black belly after breeding) either sits there or goes into the water and just swims in circles.  

I've tried staring them down, following them, hitting them (sadly), pushing them around, trapping them, and even just wasting time waiting and waiting, but in the end they don't lay their eggs.

It's impossible to find already laid eggs and baby turtles, so I cant get any scutes to make the turtle shell helmet.