Yikes that's huge! I knew they grew to that size but seeing that pic kinda puts into perspective. We have quite a few baby hammers wash up on our beach each year, allegedly it's a breeding ground and that would make sense as we have a fairly sheltered beach with a mangrove estuary for the little uns to seek refuge in.
BUT they have to get there in the first place which is a bit of a worry

I was out supping the bar monday before last, I finished one wave deep into the estuary mouth and had that Hmmm not very comfortable , best move on quickly feeling. Yep bit of a nip in the mornings just of late.