You can create some pretty stunning water or ocean effects in C4D using the free to use HOT4D, or the Houdini Ocean Toolkit. Originally a plugin for Houdini created by Drew Whitehouse based on a Jerry Tessendorf paper, HOT4D was made into a C4D plugin by valkaari.
The plugin is still far from a 1.0 version, but it can be quite useful. Here, 3D Artist Bob Walmsley walks through creating ocean effects using HOT4D in C4D. The tutorial covers setting up the ocean animation, texturing the surface, rendering the scene, and compositing in After Effects.
If you have never used the Houdini Ocean Toolkit in Cinema 4D, this is a great watch that can get you started quickly.