Diagram I made regarding Boat Tail vs Flat Base Battleship Shells
In the WW2 era, only the French and Japanese adopted the “Boat Tail” base shape for their Battleship shells.
The purpose of the boat tail on the shell base is that it allows the airflow to remain attached to the surface of the shell until it reaches the reduced diameter base, resulting in less base drag.
Base drag is caused by the low-pressure ('suction') area created directly behind the shell as it travels through the air, slowing the shell.
Interwar testing by the Japanese revealed that just adding the boat tail to their 14” shells achieved a 2,000 yard range increase with no other shell or gun modifications.
Ballistician Bryan Litz wrote that the boat tail allows the projectile to "retain velocity / energy at long range, as well as less drop and wind deflection".
The 38cm / 15” APC shells manufactured by the US firm of Crucible Steel for Richelieu in 1943 retained the boat tail base, although not exactly identical to the original French shell profile…
Many thanks to Book Author Joseph Ed Low for his assistance
Comments and corrections appreciated
statistics: Posted by PMKS — 10:09 PM - 1 day ago — Replies 9 — Views 84