Posted here as it concerns an idea for the RNZN.
I think RegR idea has some merit ,but not in the way he envisions it ..As I have said before I have no military background (apart from NZ National Service where I reached the rank of Signalman).
I propose the thought that a couple of surplus turrets be placed on a standard container base as a fully self supporting unit (hydraulics ,power etc) .The Navy could then be able to use them as additional firepower if they require them .I am aware that there are problems attached to this ,but I feel in the case of the OPV for example a gun in the front is only of some use. A LAV turret with some stabilization would be more use than an unstabilized .5 HMG. .As quite a few ships have container docks .I would surmise that some would have available power points for reefer containers.
I realise that there will be holes in my proposal so feel free to shoot me down (Mods ,do whatever you want to with this post).
Honestly this idea is about as bad IMO as having NZ develop a land-based ISO containerized Bushmaster mounting.
If additional 25 mm guns are deemed necessary for the OPV's, the RNZN would be better off acquiring Mk 38 guns, or Typhoon mountings with 25 mm guns. The NZLAV turrets are stabilized for and kitted out with optics appropriate for use on land, not firing while underway at sea in potentially pitching and rolling conditions. Why would it make sense for NZ to spend coin to spend what would likely be a fair bit of coin to take existing kit to deliver a half-arsed re-purposed capability?
To give people an idea of the cost, in 2007 the USN purchased 62 Typhoon 25 mm weapon systems in a joint contract with BAE and Rafael for USD$36 mil. with delivery by 2009. Yes, this order was a decade ago, but it worked out to less than USD$600k per weapons system. I just do not see NZ being able to either develop, or fund someone else to develop, a system which can re-use a NZLAV turret effectively while attached to an ISO container, for that kind of money per unit. Or the 2012 contract for the USCG to purchase 21 Mk 38 Mod 2 stabilized naval 25 mm guns for USD$24.2 mil.
To develop a weapons system like people have suggested is not as simple or inexpensive as just purchasing a 20' ISO container for USD$3,000, cutting a hole in the top and dropping a turret in. As an easy example, without proper reinforcement, the weight of a NZLAC turret with the gun, ammunition, sensors and crew would likely at least deform an ISO container, since those are designed to support the weight on the corners which is why they can be stacked. If weight is applied to the sides or top but not at the corners, the containers collapse, as can be seen if one looks at shipping containers people buried to create underground bunkers.
I am not going to bother going on, but from my POV the only economically viable re-use for surplus NZLAV turrets would be as a source of spares for the NZLAV fleet being kept in service. Anything else is likely to provide either an overly expensive or ineffective capability, and very likely both.