When Douglas was a child, he had two near-drowning experiences, which left in him a deep-seated fear of water. This phobia of water often ruined his fishing trips and deprived him of the joy of all water-related activities, such as canoeing, boating and swimming. He felt handicapped due to this fear and it bothered him. This is why Douglas was determined to get over his fear of water.
OR
Douglas was determined to get over his fear of water because it had ruined his fishing trips. Also, he could not enjoy water sports like canoeing, boating or swimming.
