Different style of HP book covers

[Carol]

Carol earlier:
> > What's with the raised hands for HBP? I understand all the others.

Annemehr:
> I believe they're the hands of inferi, coming up through the water,
 represented by the green waves at the top. <snip>

Carol responds:
I'll bet you're right. (Also Aleta, who made the same suggestion
offlist.) The hands and arms look somewhat distorted and the waves are
above them as if they're coming up through the water as you said.
Also, now that I look mor closely, the squarish gray thing at the top
is almost certainly the prow of a boat.

Carol, who vastly prefers the American cover art even though Harry is
left-handed and DD's right hand is uninjured