It looks like one of those underwater naval mines from WW2. It will be hollow, so that it would float, and has an attachment that would have moored it to the seabed.
The pictures I have seen of those sort of shipping mines had protrusions on them
I don't think it's a mine because it doesn't have those protrusions. It looks more like this mooring buoy. .
mooring buoy
with the connections on top and bottom?
It looks like one of those underwater naval mines from WW2. It will be hollow, so that it would float, and has an attachment that would have moored it to the seabed.
The pictures I have seen of those sort of shipping mines had protrusions on them
https://en.wikipedia.org/wiki/Naval_mine
I don't think it's a mine because it doesn't have those protrusions. It looks more like this mooring buoy. . mooring buoy with the connections on top and bottom?