Water doesn't flow "down" where the earth curves a distance away from you because "down" is towards the center on any given point on a globe- the direction gravity pulls it. Your position looks "down" to someone that's "over there".
As for preventing you from exploring, no one is. Hop on a ship or a plane (heck, buy your own) and take off for somewhere... anywhere. If the earth is flat, then every single commercial pilot in the world is in on the conspiracy. Globe is why you fly north towards the pole and back down when you go between North America and Europe- it's shorter than going around, something you wouldn't have on a flat disk.
Anyway... just a couple points to think about.
Where is the measurable curvature of oceans? Earth is 70% water, flat water.
There is no measurable curvature anywhere on Earth, so if you think you've found it, please let us know. There are millions of us that would love to see water breaking it's own law of physics and bending thousands of miles around a spheroid.
If you honestly think you can just "hop on a ship and take off" for Antarctica without Government approval, then you know nothing about the Antarctic Treaty, and you're just publicly proving that you've done zero research into this subject.
You've given us nothing worthwhile to think about, you've just offered the same tired logical fallacies we've all heard over and over again.