In 1967, Tang, Wahoo, Gudgeon, and Harder received an additional 15-foot ( 15 feet ) section (five additional frames between frames 42 and 43) to accommodate the BQG-4 Passive Underwater Fire Control Feasibility System (PUFFS) passive ranging sonar installation, with three tall domes added topside, and additional fire control equipment that enabled the use of the Mark 45 nuclear torpedo.