Ocean Borders -- Is That Really a Thing?

I tend to write about odd stuff, and this may be one of the oddest:

Question: How are ocean boundaries set?

I mean, for instance, if you’re sailing westward from the Pacific Ocean south of Australia, how do you know precisely where you've left the Pacific and entered the Indian Ocean?

There’s no flashing signs out there indicating where that boundary line is in the vastness of nothing-but-water-as-far-as-the-eye-can-see -- right?

This is something I would bet most have never given the slightest bit of attention to. Hey, I just started wondering about it after seven decades of Life.

OK. I know much smarter minds than mine have determined exactly where the equator is, the Tropic of Cancer and the Tropic of Capricorn, and all the other invisible lines of latitude and longitude encompassing the globe.

And within all of those invisible lines are “degrees” of distance to help pinpoint exact locations on the planet. 

So, say, if a plane crashes into the ocean and a passing ship sees it, rescuers or whoever can go to that exact location by using specific navigational tools.

Now I don’t want to get too deeply into the weeds here, because I’m not an oceanography nerd. But humans DO have a system to arrive at specific locations in oceanic landscapes that are far different from actual landscapes.

I.E., landscapes that involve actual land formations, human-agreed-upon boundaries and other physical attributes. And NOT simply endless, mind-numbing vistas of water and sky.

Over time, humans have worked out pretty specific boundaries for each of the five recognized world oceans:

Borders of the oceans - Wikipedia

There’s even an international organization that – since 1921 – has been charged with insuring the boundaries of the oceans are properly charted:

https://en.wikipedia.org/wiki/International_Hydrographic_Organization

But to me, it all seems a little sketchy.

Still, sailors have been criss-crossing the globe  – moving from one ocean to another – for hundreds of years and usually don’t get lost, as far as I know.

But in the end, does it REALLY matter which ocean I’m in when I get close to where they meet?

Probably not – as long as my boat doesn’t spring a leak.