The article wasn't 100% clear, but to me it seemed they depth charged something at night, yet they were able to see the oil slick? And blood? Wow, that would be a LOT of blood to make it to the surface intact and all. They thought they'd damaged a "smaller object" next the "sub"?
Mehinks they may had nailed a whale.
Oh well, maybe the divers will find something.
Alvis 3.1