Don Tolbert, systems integration officer, Marine Corps Communication-Electronics School, underwent an 8-mile swim at the Training Tank during the early hours of Dec. 19 to work toward increasing his personal standards in swimming endurance. - Don Tolbert, systems integration officer, Marine Corps Communication-Electronics School, underwent an 8-mile swim at the Training Tank during the early hours of Dec. 19 to work toward increasing his personal standards in swimming endurance.