That's an interesting point compositionally. Initially when I was looking at it I didn't really perceive it that way, but now that you mention it I can see what you mean. Thanks for the feedback!
Nice concept and atmosphere, although I'm curious as to why you chose to cut off some of the ball-and-chain at the bottom. It seems to suggest that the ball has hit the floor of the body of water, and unless this is the intent, I think the image might be better extended so that the ball ends up at least as far from the bottom edge as the largest of the bubbles is from the top edge. Other than this, well done 
Very nice work
Just my 2 cents, but there's so much motion in the background I saw it as rapidly sinking.