The tape can be found on the corpse of a diver just before the toxic water past the entrance tunnels at The Deep.
James: I swear by all that is holy, I found it. I knew it was there all along, see, it started with the rumbling. We had some minor earthquakes, you heard me right, earthquakes of all things in this neck of the woods. I knew somethin' wasn't right, and I was gonna prove 'em all wrong. All the other people at the Resort just laughing at me, well, who's laughin' now? I just discovered a fuckin' underground spaceship! And the rocket fuel leakin' off of that thing? Hell, it's making even the rocks glow! I gotta tell the President if it's the last thing I do! I'll be an American hero! Get the Medal of Honor, I bet! All right, 'nuff talkin'. Time to swim back to home, to glory, and to wipin' that damn smirk off Robbie's face! James out!