I did'nt nesscessarily read it to mean an NH90 would operate from the littoral but more off the littoral as in not have a hanger and embark it's own 90 but more have the ability to land a NH90 sized helo on a deck to support ie either from another vessel or from land as the majority of it's roles would be close to land or part of a larger force.
Whilst an organic helo is always advantageous in terms of hydro, diving support and MCM is it always if at all required?
Not always required. However, while having a helipad large enough for an NH90 could provide a few advantages in a small number of circumstances. Having a hangar large enough to accommodate one, with the inclusion of a magazine for the helicopter, provides a significantly greater number of advantageous circumstances. Having a larger hangar could allow the littoral support vessel to ferry an NH90 to or from a deployment away from NZ. At present, if NZ wanted to deploy an NH90 away from NZ for some reason, they would either need to be brought in by Canterbury, as some sort of cargo from a STUFT, or flown in as air cargo (unless the deployment is close enough to be flown to from NZ and/or friendly islands). If for some reason, NZ only needs a single helicopter (or just and extra one) at a deployment, it would be more sensible for that to be brought in when possible by something smaller than Canterbury, especially if Canterbury is already being utilized for something else.
As for the magazine, at present only the FFH's are able to support armed helicopter operations, due to a lack of hangar magazine in the OPV's and Canterbury. While I would not expect a Seaspite to often be deployed, especially armed, from the littoral vessel, including a hangar magazine gives more potential options and flexibility for future force structures and deployments.
As I have alluded to previously regarding the Project Protector vessels, it almost seems as if the particular designs and configurations selected, were specifically chosen because of how limited they were in capacity for future growth. Take the OPV's for instance. They are armed with a 25mm gun, but without significant hull and internal compartment modification, could not be armed with a larger weapon (even just switching to a 30mm Goalkeeper CIWS). While they can have embarked helicopters, they lack a hangar magazine, so no carrying LWT's, depth bombs, heli-borne AShM, or anything larger than small arms aboard a helicopter.
Absent structural changes in a dockyard, these design decisions will remain, limiting what the RNZN can task these vessels with even in areas without direct state-on-state conflicts.
It's always advantageous to have helo capability on a platform if possible because it increases the versatility of that platform. If they the ship will be large enough for a hangar then it should probably have one, even if a helos is only embarked rarely. The hangar can be utilised for other things as well, such as a temp gym, prep bay for missions etc. Whether or not the NZG is willing to pay for such a facility is another story.
Re Tods query about how often the RNZN patrols down and around the Ice. For the last two or so years, the RNZN has done one patrol down to the Ice per season (summer). I think that reflects NZG funding for EEZ and associated patroling more than anything else.
If the NZG only funds a single patrol per year, then spending any extra on ice-strengthening for a third OPV would be wasteful IMO. If the NZG was looking to maintain a presence for a significant chunk of the year (2-3 seasons per year) then having three OPV's to rotate through for training, maintenance, and deployment would make sense.
Having a third OPV (it should be of difference design, otherwise the design flaws of the current OPV's would be repeated and the person making such a selection charged with something) which is not making the compromises needed in ice-strengthening, never mind the issues with the current OPV ice strengthening, could instead be used for more patrolling aware from the ice. Leaving the two OPV's to alternate which one is going to patrol the ice that year, as well as the other non-ice patrol taskings, trainings. etc. Heck, money and displacement 'saved' on ice-strengthening could be used for a better RHIB/smallcraft launch and retrieval system, or a larger helipad and hangar. Or even a ship-mounted gun aft.
I could see how such a vessel could have/be useful for some of the S. Pacific deployments like RAMSI. IIRC the RAN sent an ACPB in support of the ADF/Ausgov detachment. Having a larger vessel with organic helicopter support and likely better comms could help in such deployments. Same goes for HADR operations where the overall threat to the vessel/crew is generally minimal, but the need for options and flexibility from the deploying vessel is important.