I had the impression there'd have to be quite a lot of changes to upgun to 155mm for RN warships, as the existing arty ammunition is charge and projectile loaded separately while 4.5 inch ammunition is fixed - wouldn't this mean substantial changes to ammunition handling procedures and equipment onboard? Perhaps it's not seen as particularly attractive given the development potential of expanded capability ammunition for more conventional naval guns.
I'm not really sure of what the work would involve or how much it would cost, I'm just wondering how much of a factor such a consideration could be.
Hmmm....
I know that I work in the industry at the 'coalface', but I would say that from my trawlling of 't'internet', THAT job is a 'Mid-life update' sorta task. To up-gun a ship, or even change from something like a 57mm to a 76mm pretty much means a complete strip/gut & rebuild of the internals of the ship, forward of any silo / bridge screen.
As a 'rough-list', you'd need to add in additional deck strengthening, & the support ribs down the side of the hull would probably be replaced. All your power supplies would have to be uprated, along with all the pipework for things like Spray systems / fire fighting / cooling, etc. Ventilation would have to be uprated. A new hoist for transfer of ammo & shells, new storage racks & ancillary equipment to move shells about, would all have to be sourced, fitted & tested.
Work like that probably needs the ship dry docked & could take up to a year / 18 months (like most refits), & to qualify that it would take that long, because of all the OTHER work that would be getting done in paralell. Then on the back of it, your ship is going to be heavier, so it'll go slower & once the work is completed, you will also have to undertake a batch of sea-trials for testing, to work out all the niggles. Rough order of cost is gonna come in at something like 100 - 150M per ship for something like a T-45 (
Note: These 'ideas' are all from MY thoughts/opinions, nothing else...... I don't think anyone has done a proper feasibility study on it !!)
The 155mm / 5" / 6" guns that are available are all AFAIK, 'double-stroke' (i.e. separate ammo & shell). Shells & propellant have to be stored separately & in comparrison to 4.5" only have about 1/2 to 2/3rds the fire rate. Also being a bigger shell mean things like additional heat is generated, which in turn slows the rate of fire, so over time you may get 'X' RPM for the 1st minute, but then you may have to slow to 'X' minus 1/4 or 'X' minus 1/2, so that the rounds go off when you want them to & not as soon as they enter the breech, due to 'hot-gun' symptoms !
But we digress....
SA