Won't the Southern Patrol Vessel require at least a basic Ice rating and an ability to handle Sea states that the Arafura class would go out of there way to avoid? The RAN are building the Arafura's with mainly tropical conditions in mind.
I suspect it depends on the intent of the idea.
AFAIK the
Arafura-class design would be unsuitable for use as the basis for a Southern Ocean patrol vessel, short of major design changes which would make it essentially an entirely different design. As I understand it, it is not merely an issue of ice-strengthening the hull, but also ensuring the design is long enough, beamy enough, and with sufficient displacement to handle the sea conditions in far southern waters. As it currently stands, the
Arafura-class design is shorter, has less beam, and is of lower displacement than the RNZN's current OPV's.
However, if the idea was not to have the
Arafura-class design be changed until it was suitable for Southern Ocean conditions, but to provide the RNZN with replacement OPV's when the current vessels reach the point of needing replacement (likely in the 2030-2035 timeframe) for non-ice/Southern Ocean patrolling, then possibly.
Surely this is a modification Australian naval shipyards could do ? Australia did build our 'protector fleet' after all.
Not a naval engineer, but I believe what would be required for a design to be "suitable" for the Southern Ocean is significantly different than the extant design. A design based off the
Harry DeWolf-class OPV for the RCN and Canadian Coastguard has been suggested as being a more suitable replacement. The basic characteristics of these vessels are ~20 m longer, 6 m greater in beam, and ~6,600 tonnes. These vessels are significantly larger than either the
Arafura-class or what is currently in service with the RNZN.