Todjaeger
Potstirrer
I agree that the OPV's will not be refitted with a larger gun, and aside from perhaps switching from a 25 mm Bushmaster to a 30 - 50 mm Bushmaster, it likely could not be refitted without significant changes to the internal structure during the refit.I agree with Toby that the Otago's with the 25mm are adequate for NZ EEZ patrols. (Even though maybe a 40mm would have been better) However, they are basically multi-agency vessels in terms of tasking. The Navy just owns and operates them.
They have never ever been considered for anything other than an assessed low threat environment from the outset. They are not the sharp end. They are not warships but constabulary and government support vessels. They will be fine in the part of the Pacific that is benign. Lucas raises some excellent points and they are of regret over many aspects of the project - but remeber the project was fiscally and ideologically strangled from the start.
Some Navies like Ireland may have 76mm on their OPV's, however they are as frontline as they will ever have in the sharp end - however we will soon have 2 upgraded Anzacs and likely to return to a 3-4 frigate fleet over the next decade or so reading the tea leaves (and noting the current governments pro-maritime policy).
Anyway it is all a moot point because they are not going to refit the OPV's with a larger gun.
However, I do think the OPV should have additional weapon mounts apart from the two M2 HMG's What I think would be appropriate would be either another Typhoon/25 mm Bushmaster or Mk 15 Phalanx (with ASuW upgrade like on the RNZN Anzacs) to cover the aft arc, or a pair of mini-Typhoon mounting positioned the port/aft and starboard/aft arcs respectively. Unfortunately, having looked at the ship schematics I am at a loss as to where such mountings could be fitted, without removing the crane and two RHIB's aft.
My thinking behind the appropriateness of such an armament upgrade, is that the OPV is indeed a RNZN owned/operated patrol and enforcement vessel, and not a warship. However, lack of overall choices in terms of equipment available for ops/deployment to the RNZN and NZDF as a whole, it is possible that the OPV's could find themselves in higher-than-expected-risk situations. Not necessarily in a situation where someone would try and use the OPV as a warship, but more in a where the gaps in weapon arc vs. smallcraft could be problematical. I am thinking specifically if an OPV was deployed as part of the multi-national anti-piracy patrols off the coast of Somalia. Given that the pirates seem to prefer boarding vessels at the stern to seize them, the lack of gun coverage aft is a vulnerability.
Now, if the OPV's are only ever operated around New Zealand and possessions it should not be an issue. Given that the RNZN is currently a two frigate-only navy, I feel it is likely that at some point, either one of the OPV's or perhaps Canterbury will be deployed as a 'show of force' to a situation where the vessel would be at risk.
Incidentally I have been trying to work out what sort of capabilities and systems would been appropriate for an OCV design that would meet both RAN and RNZN needs. Once I have finished, I will post it, but so far, it is resembling a 100 m OPV/corvette that would likely displace ~2,500 tons.
-Cheers