From Videogame Morgue File

PT-109 was a release by Mirco Games in 1975 and was one of the first microprocessor games available on the market. Up to four surface boats on two teams could battle against each other for the top score, dodging mines and grazing around obstacles to get the highest score within the time limit. The game was available only in a cocktail table format, controlled via a potentiometer and a button on the top of the cabinet.