Comments by "Frank DeMaris" (@kemarisite) on "USS St Louis - Guide 175" video.

@johnsobery no, C-20 was scrapped in 1930. The St. Louis at Pearl Harbor was CL-49, a Brooklyn (or St. Louis, depending on the source)-class light cruiser with EVEN MORE 6" guns in five triple turrets.
3
@Batmans_Pet_Goldfish I'm just going to copy this from another forum: To prevent torpedoes from becoming a navigational hazard in the event of a miss the 1907 Hague Convention VIII had a section on mines. Once a torpedo was out of fuel it was buoyant. Therefore any torpedo that missed its mark (which was a lot!) would become a random and deadly hazard to navigation. The easiest solution to this was to detonate the torps at the end of run when the fuel ran out. In later models, they were built to automatically explode when the fuel was exhausted. US submarine commanders speak of hearing 'end-or-run' explosions which told them their torpedo had missed. This may be designed as safety system, causing the torpedo to self-detonate after a certain radius.
3
@topguntopcat for worst, I would probably pick on the French and Japanese (under license) 13.2 mm heavy AA machineguns. Most of the faults of the 25 mm type 96, including the box magazine for interrupting fire, with an even more anemic projectile. At least the half-inch US and British machineguns used long belts of ammunition.
2
@UpNorth gyroscopes to complete the firing circuit only when the ship is on an even keel. Basically, the "trigger" activated by the gunnery officer merely gives the gyros permission to fire the guns. I'm seeing indications this was adopted around or during WW1.
2