Complex sentence: On 10 May 1978, flooding which began in a pump room in the aft portion of the ship rose to a height of before it was controlled and spread into food storage rooms, destroying most of the ship's stocks of fresh milk and produce.
Split into simpler sentences: On 10 May 1978, flooding, which began in a pump room in the aft portion of the ship, rose to a height of before it was controlled. The flood spread into food storage rooms, destroying most of the ship's stocks of fresh milk and produce.