Well I've posted 5-AI at ORG to get more input or reports of error.
B += x
hmm... no difficulties reported so far with file loading/playing...

In meantime, I have written up Battleship 6 AI versus AI, and tested every other square random coverage versus every 2 squares random coverage until AI gets a hit. Every 2 squares clearly edges out an every other square coverage until the Destroyer (length 2) has been found and sunk.

As noted elsewhere:
For 100 games in a row here is sample of results mod 2 - mod 3:
50-50 the closest they ever came!
I'd say 40 something versus 50 something was typical.

Here is first test when running 20 games:

Here is typical result for 100 games:

Here is the closest the two methods came, a tie!
B += x