Cinema 4D has a few options for ocean shaders, including a port of the Houdini Ocean Toolkit. You can now add another to that list of ocean shaders / deformers, because aaOcean has been ported over to C4D thanks to Niklas Rosenstein.
aaOcean is Amaan Akram’s ocean simulation system that like many others, is based on the Tessendorf waves system. The open source Ocean suite enjoyed residence in Maya, Houdini, Mental Ray, Arnold, and Softimage. The library’s open sea ocean waves are based on measured and statistical wave movement data.
aaOcean suite provides both shaders and deformers to work with. The deformers let you run large-scale ocean simulations on low resolution stand-in geometry, while working. A higher resolution simulation can be swapped out at render-time. The Ocean suite is also a little more intelligent about where to add the details in the ocean simulation, through frequency spectrum sampling.
Rosenstein mentions that the initial port of the ocean suite tools were sponsored by Partner Ship Design GmbH. That being said, you can download and use the aaOcean Suite in Cinema 4D by visiting NIKLAS ROSENSTEIN’s DLC page here.