I think the Phalanx is an easier sell simply because we already have them and would meet the minimum requirements. I think its surface model is probably more suitable for a OPV than RAM. Really it doesn't matter, if space, weight and power is allocated, then SeaRAM or Phalanx (or nothing or some future system) could go in depending on what we have. I would imagine if we ever wanted to move these ships on (continuous build etc) then having the ability to mount something defensive like that I think would be a big plus.
Phalanx might be an easier sell, however IMO it is becoming a more limited CIWS weapon. Between the range and weight of shot of the 20 mm rounds, many of the potential AShM threats could not be effectively defeated by the Phalanx any more, which is part of the reason why the USN worked to have the Millenium Gun developed.
While I agree that there should be options to have a layered defence, at this point though, it does appear that the Phalanx would not be an option in many cases against aerial threats. There are just too many missiles which can come in too fast for a Phalanx to damage sufficiently to prevent impact, once the missile comes within range of the Phalanx. The -b mod does add an anti-surface/FAC role, but other weapons are already available to cover smallcraft (some of which can also do better at anti-air)
All this talk of ESSM's, multiple Millennium guns and ASM's for the OPV's is complete nonsense.
The realist in me tells me the most we can expect is a 57/76mm gun plus one or two 25mm's. At a stretch we might get a Phalanx/Searam.
You may well be correct. However, given the various requirement iterations for the patrol capability over the last 20+ years, there is the potential that some might need to be 'upgunned' and/or have the flexibility to be upgunned.
Much of the will be determined by both the planned, and actual conops for the OPV's. As has been observed with the ACPB's (and the FCPB's before them...) the RAN needs to conduct certain types of operations, in certain areas, and under certain conditions, and the vessels purchased to conduct these operations need to be up to the task. Using the ACPB's as an example, while they may have met what was specified in the contract (for the most part) in terms of capabilities, the actual circumstances which the ACPB's operated in were a bit different.
By increasing either the overall capability, or the potential capability (via fitted for but not with, and/or mission modules) of the OPV's, then the utility of the OPV can be increased beyond just the improved range and sea-keeping when compared with earlier patrol forces.
If the RAN were to deploy a vessel on anti-piracy patrols, armed to the level of the ACPB's, then depending on just who/where the pirates were, the RAN vessel might be facing peer or near-peer level forces in terms of hardware. The only time you have that sort of fight, is when you have no other choice.
One of the other, potentially important, considerations is that with the mission modules becoming more prevalent, more future RAN vessels might be set to use such modules. Under such circumstances, it would seem sensible to allow the OPV's and future frigates/destroyers to be able to trade off some of the minor weapons systems depending on where vessels are being deployed. The RAN already does that to a degree with the pool of Mk 15 Phalanx CIWS.
Using the Danish Stanflex system as an example, a number of the RoDN vessels which have four Stanflex module bays can be fitted with 48 ESSM, a respectable missile loadout for limited area air defence. That very same sort of vessel could also get re-tasked after a port visit, with ASW operations, with one or more of the module bays getting fitted with LWT launchers, and so on.
Some of the discussion has been about the fitout, capabilities, and integration issues with various weapon systems. Other parts of the discussion has been about potential concerns with the OPV, since some vessel selections are more limited, or are much more difficult to alter/increase the capability loadout after construction. The current RNZN OPV's being a prime example of such limited.
Please keep in mind (the active Kiwis on here should already know this) that I do not do this to have a go at the RNZN, but to illustrate how much forethought, or the lack of forethought (or possibly deliberate decisions based upon ideology...) can impact options. Like the ACPB's, the Kiwi OPV's are armed with a 25 mm as a main gun, with what appears to be compartment space immediately beneath the mounting. This immediately limits what the 25 mm gun could be upgunned to, or replaced with, since anything requiring deck penetration would require drydocking so the internals could be rearranged. It is also an open question on whether or not the space could be used for a different, non-penetrating gun, since some mountings require differently levels of reinforcement. Looking over the rest of the ship, there also is not really any place open to mount another 25 mm gun (meaning no 360 degree fire arc) or a CIWS. This means the RNZN OPV is sufficiently armed to damage and possibly sink civilian vessels after potentially extended periods of firing, as well as smallcraft which can be kept within the firing arc of the OPV's main gun. One of the other (IMO very big and/or deliberate) oversights is the hangar magazine, or rather, the lack of one. This basically means that while the OPV can have an embarked helicopter, it is essentially unarmed except for small arms which can be brought from other magazines within the ship. This very much limits just how useful an embarked helicopter can be, especially if patrolling in an area where an armed response would be advisable. Due to the lack of a magazine, the armed helicopter response it limited to perhaps a door-mounted MG, instead having options for a gun pod, AShM, Hellfire or other AGM, LWT, depth bombs, etc.
Again, it is some of this sort of forethought which can permit a greater range of responses in the future.
