It is a minor annoyance having your Companion disappear whenever you enter a body of water. I figure this must be some limitation of the pathfinding system that NPCs use, but maybe Companions can just swim in the direction of the player regardless of what obstacles may be in their way? Their combat ability would have to be disabled while they're in water, naturally.

I managed to capture a screenshot of Sharp-as-Night standing on a platform that is submerged in water. At this depth, a character would normally be doing swimming animations.
Now that we have mount swimming support in U47, can the same be given to Companions? @ZOS_Kevin