Colin P said:
Noted that part way through the video they raised the gun up, was that part of a drill or a standard procedure to prevent water ingress? I note that on older ships they often rotated a forward turret so the guns pointed aft to reduce water ingress.
You can see that the picture "jumps" just before the gun muzzle angle changes, suggesting some time lapse. The angle up position is, by the way, the normal position for the 57mm cal gun: look at them next time the ships are alongside . So this has nothing to do with water ingress, which the muzzle rubber cover amply stops.
By the way, the reason we used to turn the forward turrets so the muzzles faced aft on the old steamers had nothing to do with water ingress. It was to minimize the water wash pulling the turret off the deck or skewing it inside its base. You see, the old mechanical gun turrets (the twin 3'50 or twin 3'70) were not attached to the ship. They rested from their own weight into the "tube" opening that went through all the decks down to the magazine below. As a result, the "elevator effect" on the bow during stormy weather caused the whole turret to "free float" and jump out of its tube. To prevent that, we turned them in to minimize the force exerted by the water and we actually tied the turrets down to the deck with steel wire stropes made for that purpose.
You may have heard that many, many moons ago, the PRO class had a twin 3'50 right on their bow (known as "bow chaser" - and originally installed so they would qualify as "warships" for the Panama canal reduced fees purpose, or so the story goes). One night, in a bad storm, PROTECTEUR's was washed right clean by the sea. Bow went up, bow came crashing down, spray all over the place including on the bridge windows, when spray cleared, the gun was gone. Lore has it that the OOW was so stunned, he could not explain to the captain and simply said on the phone: "you better come up and see this for yourself, sir", leading to a record breaking time for the "CO's cabin to bridge" sprint on an AOR. After that incident, it was thought better to remove the guns from the class.