The legend of the “submarine” is not something out of historical tales long forgotten. Just last year people claimed the submarine was spotted near Cape Town.
The shark or its descendants is said to be as big as a submarine, hence the name. The fact is the shark is real although it might not be the same shark, it might also not be the size of a submarine.
Experts and people that claimed to have seen the shark say it looks like a megalodon. Could there be Megolodins still today coming from Antarctica and no one knows about it?
More about the legend can be seen here at the Cape Town submarine shark legend