Unity3d Underwater Effect

underwater.js

//This script enables underwater effects. Attach to main camera.

//Define variables
var underwaterLevel = 7;

//The scene's default fog settings
private var defaultFog;
private var defaultFogColor;
private var defaultFogDensity;
private var defaultSkybox;
var noSkybox : Material;

function Start () {
    //Initilize defaults
    defaultFog = RenderSettings.fog;
    defaultFogColor = RenderSettings.fogColor;
    defaultFogDensity = RenderSettings.fogDensity;
    defaultSkybox = RenderSettings.skybox;

    //Set the background color
    camera.backgroundColor = Color (0, 0.4, 0.7, 1);
}

function Update () {
    if (transform.position.y < underwaterLevel) {
        RenderSettings.fog = true;
        RenderSettings.fogColor = Color (0, 0.4, 0.7, 0.6);
        RenderSettings.fogDensity = 0.04;
        RenderSettings.skybox = noSkybox;
    }

    else {
        RenderSettings.fog = defaultFog;
        RenderSettings.fogColor = defaultFogColor;
        RenderSettings.fogDensity = defaultFogDensity;
        RenderSettings.skybox = defaultSkybox;
    }
}