Rhino Water / Ocean Material on Ground plane Impossible?

Hi all you Rhino render experts out there.
Im trying to produce some raytraced renders for a marine project im working on. I have tried unsuccessfully ever since rhino 5 came out to make and apply a water / ocean material to the rhino ground plane and create raytraced renders using the inbuilt rhino render engine. I have had the same problem with Rhino 6, 7 and now 8. I have used many third-party render engines that plugin into rhino such as Thea render, Maxell, Flamingo that all accomplish this task easily. its just the rhino render engine that seems to have always has this problem.
Are any of you guys able to edit the water material I have created in the attached 3dm file to get it to work? Im guessing there are some set of unicorn settings / parameters that might make it possible but im yet to have figured it out over the years.
Note the file units need to be millimetres
I have made a short screencast illustrating the problem and uploaded it to YouTube if you are the visual type. https://youtu.be/XanjtRRvfnk
Any help greatly appreciated.
Water Material.3dm (6.4 MB)

This link to another forum discussion is good:

Thanks John