Machinery, armament, and the 186-mine load

Four water-tube boilers fed two three-cylinder triple-expansion engines, producing about 6,600 metric horsepower for 20 knots and a range of 3,530 nautical miles at 9 knots. A complement of 11 officers and 197 men served eight single 8.8-centimetre guns and handled up to 186 mines. The payload gave the ships considerable route-denial capacity, but their speed would barely keep them ahead of HMS Dreadnought, let alone later fast warships. Nautilus was laid down in 1905 and completed in 1907, while Albatross was laid down in 1907 and completed in 1908, another reason to be cautious about treating their specifications as exact duplicates. The design traded speed and firepower for economical endurance and a heavy mine load.