If closely mimicking physical Battleship (or similar games that hide state by physical occlusion) is important, you could add a 2-retroreflective-sided board ve

If closely mimicking physical Battleship (or similar games that hide state by physical occlusion) is important, you could add a 2-retroreflective-sided board vertically in the middle to block each player’s view of the other’s hands. But a software game has many other possible mechanics that don’t work with a physical plastic board and pegs, so more likely people will just modify the game so that seeing someone’s hand motions doesn’t reveal hidden state.