The W.23 followed the design philosophy for all flying boat biplanes built by Hansa-Brandenburg, including a swept lower wing, wing floats, pusher engine arrangement, and a single-step hull. Although similar to design to the Hansa-Brandenburg W.18, it differed in having a longer fuselage. Three aircraft (MN 1647-1649) were delivered from June 1917 to January 1918, but flight characteristics were deemed poor.[1]
Owers, Colin A. (2015). Hansa-Brandenburg Aircraft of WWI: Volume 2–Biplane Seaplanes. Great War Aviation Centennial Series. Vol. 18. n.p.: Aeronaut Books. ISBN978-1-935881-32-2.