Re the "modern, single 4.5" gunned frigate vs the US Iowa class battleship", I know which my money would be on. The battleship.
Built to take huge amounts of punishment, and keep dishing it out. Upwards of 12" of belt armour. and nine 16" main turret guns each capable of independent targeting, and hitting further than the 4.5" weapon. And lets not forget the Iowa-class had a targeting computer that could utilise radar.
HMS Pinnypoor fires 25 rounds per minute. But is this sustainable? The delivered gun system had problems in the Falklands. Would the 4.5" rounds be capable of penetrating 12-18" of armour? The Type 23's armour would be as useful as tissue paper against a 16" round from the Iowa, and I'd doubt it would survive more than two hits.
It's speed may not confer much advantage, as nine 1 ton shells arriving all at once would overcome the 4.5"'s ability to shoot each down (ignoring Sea-Wolf, etc). And a bracketed shot could cause concussion damage to the Type 23. The Iowa could - or try to - fight her way to within 14km, and then bring the secondary armament to bear.
This is compared with the Iowa-class of WW2-Vietnam. The Type 23 would last as long it took the Harpoon to arrive from the 1986 class refit model.
Moot points, I know. But the last upgrade to the Type 23/45 (the 155mm / 6" gun) was scrapped due to a budget-cu^H^H^H^H SDR...
Biting the hand that feeds IT
