Complex sentence: Not expecting a ship-to-ship confrontation, it took the crews of the two Imperial battleships several minutes to switch to armor-piercing ammunition, and "San Francisco", almost helpless to defend herself, managed to momentarily sail clear of the melee.
Split into simpler sentences: Not expecting a ship-to-ship confrontation, it took the crews of the two Imperial battleships several minutes to switch to armor-piercing ammunition. Nevertheless, "San Francisco", almost helpless to defend herself, managed to momentarily sail clear of the melee.