What is it?

Originally Posted by Blacklight

Looking at the zig zag path that guy is doing. I would have crash dived long before. Why the hell is he staying on the surface !?!

According to what I'd read, they'd already been damaged in a prior attack. That's not a wake you see but the oil slick they're leaving behind. There are several reasons they might be on the surface: damaged electric engines, damaged compressors and no reserve compressed air, damaged pressure hull just to name a few. I'm sure if they'd been able to submerge they sure would have!