Hi there Yardmaster Welcome to Subsim all Destroyers and Escorts have Racks.
Racks feed the depth charge throwers or the stern droppers like a guns magazine so to speak
The Screen shots below are from GWX3 Mod for SH3 Museum
Early war 1940 AB Class Destroyer no throwers just droppers
1941 AB Class Destroyer with throwers and stern droppers
Captain Class Frigate 1943
four throwers on each side plus two rollers off the stern a 10 charge pattern
B for Baker dropped ouch