RIP Arthur C Clarke. He was arguably the most important single person to the early days of space exploration - a position roughly analogous with that of Alan Turing's to the genesis of computing. Incidentally he also had a fascination for the ocean and was a keen diver.
If you've not read any of his I recommend The Songs of Distant Earth, Rendezvous with Rama, Childhood's End and, of course, 2001: A Space Odyssey. His short story collections Tales from the White Hart and The Nine Billion Names of God are also essential reading: the latter eponymous story ending with a line that always gives me goosebumps.