Each submarine is equipped with three Garden Island-Hedemora HV V18b/15Ub (VB210) 18-cylinder diesel engines, which are each connected to a 1,400 kW, 440-volt DC Jeumont-Schneider generator. The combined electrical generation capability of each submarine is 4.2 megawatts. The Hedemora diesels were chosen because of modular construction, which made servicing easier; they could be installed three across in the available space, while other contenders required at least two banks of two; and they had turbochargers driven by the exhaust gas. Fifteen fuel tanks are located throughout the submarine: they must be used in specific sequences to preserve the submarine's buoyancy and trim.