Complex sentence: By mid-October the entire Central Fleet had been sunk by Japanese aircraft leaving the Ying Swei the sole ship of the fleet and it was decided that the Ying Swei's naval artillery would be better used as shore batteries.
Split into simpler sentences: By mid-October the entire Central Fleet had been sunk by Japanese aircraft leaving the Ying Swei the sole ship of the fleet. It was then decided that the Ying Swei's naval artillery would be better used as shore batteries.