I made a quick sketch, it represents what I think would be a nice UI, we don't have to focus on it right now, but It can't be bad to think about what the user will see.
The title 'USER FLOAT' can change if the user changes the "switch" above the "NEW GAME" button, when that switch is switched It may display our own board (the board that the enemy is shooting).
On top of the "radar", that is, the green boxes, there are three counters, Shots taken, Hits, and Enemies, that may display how many ships we still have to sink.
I gave the HELP and NEW GAME buttons a round, kind of emergency button feel,
and I imagine the "radar" with a radar feel to it, like a green screen, and the same
goes for the Shots Hits and Enemies boxes.
That's it, they're just ideas, so we can start from somewhere with the UI.