Water Clip Proxies - NeisesMike/VehicleFramework GitHub Wiki
Water Clip Proxies prevent the ocean surface from entering your vehicle.
It would obviously be weird for the water surface to appear inside your submarine.
ModVehicle has the field:
public virtual List<GameObject> WaterClipProxies => new List<GameObject>();
Each WaterClipProxy GameObject should have no components. The transform itself should be scaled in order to change the shape and size of the proxy. The easiest way to do this is to initially create the proxy as a 3D Object > Cube. Unity Editor will make the cube with a mesh renderer and box collider. That makes it easy to see the volume of the proxy. But before you're done you should delete those extra components, leaving just the transform.
Try not to make the proxies encompass more space than the interior of your vehicle. It's weird to see the water surface disappear around the "corners" of a vehicle.
Fewer waterclip proxies is better. They don't really play well together.