Which 20th century battleship featured artillery with a specially reinforced barrel and steam turbine propulsion?
Built-up gun A built-up gun is artillery with a specially reinforced barrel. An inner tube of metal stretches within its elastic limit under the pressure of confined powder gases to transmit stress to outer cylinders that are under tension. Concentric metal cylinders or wire windings are assembled to minimize the weight required to resist the pressure of powder gases pushing a projectile out of the barrel. Built-up construction was the norm for guns mounted aboard 20th century Dreadnoughts and contemporary railway guns, coastal artillery, and siege guns through World War II.
L 20 α-class battleship L 20 α was a design plan for a class of battleships to be built in 1918 for the Kaiserliche Marine during World War I. The design was selected on 2 October 1917, and construction was to have started 11 September 1918. The ships would have been significantly larger than the preceding "Bayern"-class battleship s, at 238 m long, compared to 180 m for the preceding ships. The ships would have been the first German warship to have mounted guns larger than 38 cm . However, Germany's declining war situation and the transfer of emphasis within the Navy from capital ships to submarines meant that the ships would never be constructed.