Gunboat submarines
“Gunboat” submarines with two 5″/25 (12.7 cm) guns and centralized fire control. The submarine closest to the picture appears to be USS Sennet (SS-408). Note the two 5″/25s on deck and two 40mm guns on her sail
laststandonzombieisland
Weapons, Wars, Preparation and Security from a recovering gun nut turned bad writer