Operator of Unit #1 stated that while returning home on PWC his vision was very limited due to the sun. He stated that he didn't make eye contact with unit #2 until he was about to strike unit #2. Unit #1 made abrupt turn to the right in an attempt to avoid Unit# 2 but was unsuccessful. Unit# 1 struck unit #2 at the rear starboard corner. Operator of Unit #2 confirmed this statement. There were no injuries.