The prefix (and not a suffix) “вы-” means here (in movement's verbs) a movement from a limited space in a wider one space.
"выйти" в море, в поле, в степь,в космос, выйти на простор..

"Войти" will mean the opposite,enter in a more limited space.
"войти" в комнату, в порт, в бухту ... в женщину:>

As said above - you can "войти в море" also - but this will mean the entry into the very water of the sea.
But we don’t say at this style for submarines, usually about life land creatures only. 

Or, for a more global case -"эскадра  вошла в Черное Море" (but also from a more unlimited, larger space - from the Mediterranean to the Black, for example);

The same applies to other verbs of movement, such as выехать-въехать, вылететь-влететь, etc...