http://www.navantia.es/irj/go/km/docs/documents/Portal%20Navantia/Imagenes/productos/pdf.gif" border="0" />
We don't need a WW2 sized threat to justify the sorts of ships that I am talking about. We just need one nation that we are having a disagreement over some islands to our north who happens to have 3 or 4 reasonably modern DE subs. We have a couple of those and all that they would have to do is to SAY that they are going to hit Aussie coastal shipping and they would tie up half the ships that we can currently deploy. We can't afford that so we need a cheaper, more numerous solution.
As for the plausibility of PAR's on Corvettes LM didn't design the SPY-1K not to work. I know that using it or a smaller CEAFAR on a Corvette would necessitate using smaller missiles, but I'd guess that that ESSM can tackle a brace of sub launched missiles coming at a convoy. Sea skimmers wouldn't be detected by radar much beyond the ESSM's range anyway so the shorter range probably wouldn't matter. Having a stealthy corvette wouldn't help in that situation either as the targets are the ships that it is escorting which have a RCS the size of a well, bulk freighter.
As for pirates there was an article in the Australian about those today. Apparently we have too small a merchant fleet to be too bothered by them. Also I'm pretty sure that most of the merchant ships routed to Australia don't pass through the worst areas like the Gulf of Aden or the Straits of Malacca. It isn't one of our defence priorities.
1. Fisheries protection and smuggling is.
Our patrol boat fleet has that pretty much covered up north. OPV's like NZ has bought might be useful for policing the Southern Ocean against toothfishermen and the like, but I'm not sure that the problem is big enough to justify it.
Counterargument-your OPVs are too short-enduranced and under-gunned to perform the mission described in your AO. You need the the blue water hull capability to operate as well as the enforcement tools..One of those tools is the helo and the boat party.
2. ESSM is a fairly big and robust rocket. It actually outperforms ASTER.........significantly. it needs a fairly hefty radar to make full use of its potential. The rockets a small corvette might carry are more akin to RAM or Barak.
As I have already pointed out LM has already designed a corvette-sized AEGIS. They didn't do it with RAM or Barak in mind. A 1500 tonne hull could easily handle a couple of 8 packs of ESSM, which would suffice for our purposes. The 1000 tonne Thai Ratanakosin Class Corvette carries the 24 Aspide which is Sparrow-based so it is well and truely do-able.
Counterargument.
Aspide Mk1/Mk2
Specifications
Manafacturer
Selenia
Date Deployed
1987
Range