>>760
OH GOD, I FINALLY FOUND OUT HOW TO GET THERE HAHAHA and I believe I've just found my new favorite area on this game. I'll explain it because it's not something too obvious, although it's nothing on a Uboa level of dedication.
So yeah, use the map on that other post to get to the submarine. If it's not open, follow the instructions on that thread. After getting inside, sit on the only chair left, and IT'S BUTTON MASHING TIME! The girl obviously doesn't like that, so she'll do a "what the hell are you doing" at you. Ignore her! NOW THE FUN PART: in order to get to the deep handy ocean, you'll need to set an event there to 2400. It starts at 0, I think. And how do you increase it? Obviously, by pressing that button which the girl dislikes. Every time you press it, you'll hear a number of clicks - from 1 to 6, I think - and those clicks are the amount of times the button in front of you was pressed. So yeah, enjoy wasting 5 minutes or so of your life pressing X, preferentially with a cake on your head.
After some time, you'll notice that the background slows down drastically (possibly easier to see if you get the submarine transparent by talking to the girl) and the sonar noise that's been playing every 8 seconds starts to sound really different due to being slowed down. When this happens, just leave through the ladder, and enjoy the straightforward but somewhat huge underwater maze.