With our thanks to Lazer_one for allowing to publish the drawing
The local Dutch newspaper Middelburgsche Courant dated 9 June 1877 published a small news item according to which the Italian navy fitted her newly built armoured turret ship Duilio out with a sort of armoured dry dock in the stern in which a torpedo boat was hiding. (1) In case the Duilio approached a hostile ship close enough was the torpedo boat launched for an attack and afterwards returning to her hiding place.
Note
1. This must be the Caio Duilio, an iron battleship or turret ship with a displacement of 11,138 long tons or 11,317 tons standard and 12,267 long tons or 12,464 tons full load and with the dimensions 102,2 x 19,79 x 78,8 metres. Her two double expansion steam engines and eight coal fired boilers supplied 7,710 hp allowing a design speed of 15 knots and a maximum range pf 3,760 nautical miles of course at a lower speed. Her crew numbered 420 men. She was armed with 2-17’& muzzle loaders, 3-4’7: guns, 2-3’guns, 8-2.2”guns, 22-1.5” and finally 3 torpedo tubes. The armour consisted of a 22” waterline belt, 18” gunturrets and a 16” citadel. The building was made public by the Italian minister of navy admiral Simone Arturo Saint-Bon in March 1873. There were three of these battleships to be built and which were to be the most powerful warships of their time as designed by Benedetto Brin. The Caio Duilio was laid down at La Spezia 24 April 1873, launched 8 May 1876, commissioned 6 January 1880, decommissioned 1906 and finally broken up in 1909. Her sister ship was the Dandalo, the third one was never realized.