[LukeFF]

Originally Posted by Orion2012

Also, if the deck gun were implemented properly. It would take time to prepare the gun, as well as set the ammo chain up. Some of the ammo would have to be lifted into the conning tower and out the back hatch for access to the deck gun. These shells weigh a few pounds and lifting them would take time.

My favorite reference for this:

There was a ready locker for the 5" gun, on the deck, that provided a small, immediately available store of shells. When those rounds were exhausted ammo was passed up from below the crew's mess. For the aft 5" gun, on some boats, there was an ammo hatch located in the after port side of the crew's mess, through the pressure hull, to the after 5". There would be a loading party passing ammo from the magazine, which is below the living deck level to the ammo handlers loading it through the hatch. The standard procedure was to have a guy drop down below the crew's mess deck into the ammo locker. He passed ammo up to guys in the mess who would pass it forward to the Control Room. In the forward section was access to the gun loading trunk, passing the ammo overhead, up through the hatch, guys on the deck could reach down through the hatch in the forward sail and then pass it around the sail and aft to the gun. The job of passing the ammo up from the ammo locker or from the control room up through the ammo hatch was the job of the VERY strong. It didn't take many 65 pound shells being shoved up over your head to wear down even them.

Deck Fire Control System and Organization:
On battle surfacing, the 5"/25 crew comes topside through the conning tower hatch, drops down to the deck and the loaders open the ready locker to grab the shells as the rest position on the gun and train on the target. If the seas allowed, some of the guys could scramble up the ammo loading hatch in the forward overhead of the control room. The 5"/25 is manned by a gun captain, pointer, trainer, sight setter, and loader. The gunnery officer takes station in an elevated position in the periscope shears to direct the gun crew and to spot. The conning tower relays target range to the gunnery officer via the 7MC circuit. Ranges are obtained from the radar or the generating TDC on the cigarette deck. The sight setter sets in firing range and zero deflection angle for the first shot, then sets sights thereafter in accordance with spots received from the Gunnery Officer. Whistle signals used in conjunction with securing battle surface stations are:
1 blast = Cease fire,
2 blasts = Secure mount properly and lay below,
3 blasts = Cease fire and lay below immediately without securing the mount.

From http://www.bergall.org/320/patrol/deckguns.html