Game mode: Private Testlive
In standard player mode consistently swimming eats the stamina. floating/treading water continues to deplete the stamina.
In Admin panel > Cheat(self) > NoSprintCost
Swimming continues to deplete stamina whether swimming or treading water.
Alternatively, Admin panel > Cheat(self) > Cloak
Using the map, right click teleport to any location, upon rezzing, Cloak has vanished.