the outboard propellers and the remaining four were allocated to the turbines that drove the center shafts. The engines were rated at for a top speed of , with projected service performance of for at normal displacement. On sea trials, Trieste only reached and Trento managed slightly less than that; these speeds could only be reached on a very light displacement, and in service, her practical top speed was only . The ships had a storage capacity of of fuel oil, which provided a cruising range of at a speed of . During refits in early 1940, funnel caps were added to reduce smoke interference with the masts. Armament and armor Trento and Trieste were armed with a main battery of eight Mod 24 50-caliber guns in four gun turrets; each turret carried the guns in a single cradle rather than independent mounts. The turrets were arranged in superfiring pairs forward and aft, and allowed for elevation to 45 degrees, for a maximum range of . They had a rate of fire of three rounds per minute, and the guns had to reset to 15 degrees to reload. The turrets were electrically operated, including the training and elevation gear and the ammunition hoists. The guns suffered from excessive shell dispersion, like many other Italian guns of the period. Initially supplied with shells fired at a muzzle velocity of , the shells and propellant charges were reduced—to at —in an unsuccessful attempt to tighten shell grouping. The problem was in large part due to poor quality control in Italian munition factories, which failed to ensure tight manufacturing tolerances necessary for accurate shells. In addition, the single cradle mounts required the guns to be very close together; this caused the shells to interfere with each other in flight and contributed to the dispersion problem. Fire control was provided by a pair of Barr & Stroud coincidence rangefinders. Anti-aircraft defense was provided by a battery of sixteen 47-cal. guns in twin mounts, four Vickers-Terni 40 mm/39 guns in single mounts and four machine guns. The 100 mm guns were copies of Austro-Hungarian guns designed in 1910 by Škoda that were placed in newly designed dual-purpose mounts that elevated to 85 degrees for a maximum range of . In addition to the gun armament, they carried eight torpedo tubes in four deck mounted twin launchers. The ships' secondary batteries were revised several times during