I kinda see the separation but I don't feel it's avery strong example. What separation are you trying to show, sky from water? The separation of the clouds? An emotional separation? I just am unable too undestrand what separation it is you are trying to portray. I do on the other hand love the wonderfull blue tone to this shot.
Love the light on the sea, not so sure about the blue tones of the more distant clouds. Your cropping, or framing, has reduced the impact of that ragged edge of the top clouds though - I would think the impact would come more from the passing of them, and there just isn't enough of them in shot to generate that impact.