& the making of
For the ocean surface, I followed Bob Walmsley's Realistic Ocean Tutorial Part 1 & 2.
He used a free plugin called HOT4D:
You can download it from here:
In After Effects, I tracked three corners of the rendered sea surface and applied corner pin. This allows me to input the tracking data to the solid layer.
Then I composited whatever I want, using the solid layer as a matt.