Water4 Depth problem

I have found an amazing ocean script here: http://wiki.unity3d.com/index.php/Ocean

I have tried to apply the water4 advanced example mesh render and it generates something like the picture you see below

Now I intend to write my own shader, but for future reference, would like to know why this would happen inside Unity.

It seems when there is no background behind the conical mesh that the script renders, it makes the backside of the mesh appear up front, but this will only happen on half the mesh, as the other half looks perfect. It's the same for deferred or forward.