Fear of the Ocean

I don't think I've ever been on a boat and been out so far at sea where I could not see land. I have this suspicion/worry that if I were ever out on a boat/ship in the open ocean, that I might react with some internal terror, as though I need land to feel safe.

It may be connected to my survival instinct, like I am aware that I'm not a great swimmer so if I'm on a boat out at sea, I need that boat to ensure my safety. Whereas if I can still see land in the distance, I have more of a chance of getting back and remaining alive. The idea also feels claustrophobic somehow.

I don't know though, it seems like this may be a fear that's not always been there. And I am not 100% sure if I would really have an adverse reaction if I were out at sea.

Anyone else ever had similar feelings?