TIL That the only 18" gun the US Navy developed, was used as ballast on a hospital ship (USS Repose), but never deployed on a battleship.

https://apps.dtic.mil/sti/tr/pdf/ADA183947.pdf
#til #todayilearned
https://www.reddit.com/r/todayilearned/comments/1g2awn7/til_that_the_only_18_gun_the_us_navy_developed/