In the lower right corner you can see what looks like a gun port.  It was probably used to eject garbage from the galley.  This opening would have been underwater only during the roughest seas, and it would have been about as water-tight as technology could make it.

It would seem that the row of gun ports above would have plenty of freeboard even when maneuvering.  This turns out to be not true.  It was this row of gunports which were left open during VASA's first cruise and through which the waters of Stockholm harbor rushed, sinking the ship.