Very nice figure. I tried him in the bathtub, the foot weights obviously make him sink to the bottom, but the air pocket in his head keeps him upright.
If I was still a child, or had a child of the right age, I could see this little chap exploring rockpools at the seaside for hours on end. A great companion for a waterside trip anywhere.
If diving him with the rope, it's wise to tie the rope on. I used the hook, but it unhooks very easily, and it'd be a shame to lose the guy in deeper water.