While a hospital ship would be something very good to have in service, as Abe pointed out, they can have enormously large requirements in terms of medical personnel.
A small hospital ship of some type might be possible, but that would still potentially require the ADF to add a number of medical personnel, or concentrate much of the ADF medical response... With the potential of losing the personnel in a sudden event.
A hospital ship on the order of the USN
Mercy-class would be prohibitively expensive and suck up valuable resources, and I am dubious as to its effectiveness and value for money in anything less than combat or regional disaster zones (Haiti, tsunami, etc.). However, there is merit in thinking a bit smaller at a semi-permanent Pacific Partnership type mission.
The concept would be a smaller vessel of about 8000t to a commercial design (it isn't a warship after all, perhaps a modified expedition cruise ship type) incorporating a flight-deck and single hanger, the ability to carry, launch and recover small LCVPs and launches, as well as the their patients. It would be interesting to see how a small LPD like the
Endurance-class might be well suited to this role, with a sheltered area for the transfer of patients.
With such a size it needn't cost a fortune to run or crew, in fact it doesn't need to be heavy on RAN personnel if an RFA approach is taken. For some roles you could use reservists; "How would you like to do your two weeks on a South Pacific cruise? Oh, you would?"
On the medical side, there would be some ADF medical personnel (a large number of whom are reservists) but it doesn't all have to be ADF. As a white-hulled hospital ship instead of a gray-hulled warship there might be scope for a partnership with medical NGOs such as the Aust Red Cross or MSF, a link up with other military medical corps from NZ or US or regional allies such as France, Singapore, Malaysia, Korea, Taiwan (who are trying to gain influence in the Asia-Pacific region) or Japan.
At this point, I would like to mention China (PRC that is). It would be an ideal way to work together with the PLA on a project that is politically positive. I am of the opinion that increasing tensions and a military build-up is neither desirable nor inevitable. I think that the Chinese have shown themselves to be pragmatists in their economic and social reform, and a Soviet style military stand off may not be necessary if it is possible to engage the Chinese and include them more. Unlike the Cold War, the interests of the West and China coincide much more, and this is likely to continue despite a competition for resources and power.
An ongoing partnership in giving medical aid would help with a country that is reticent about participating in peace-keeping or other interventionist roles.
The problem that I have had with the Pacific Partnership is that it comes in and expends resources quickly in a targeted area and then departs with no guarantee they will be back the next year or even the year after. It is difficult to have a lasting and meaningful effect under such circumstances. But what if a medical mission is ongoing, with annual visits by the same medical team who has access to treatment records from previous doctors/health professionals and is able to check up on outcomes and continue to sustain community health programs?
It would also be a valuable teaching tool, not just for Australian medical/health services students but also those from the Pacific Islands nations as well, who could go on to sustain community health programs between visits. If there was interest and capacity you could expand services offered beyond medical ones and offer others of community benefit, such as engineering and education.
Such a vessel could become an agent of stability and support for isolated island communities whose national governments may not have the resources to provide even basic services, or a much need capability boost to existing services. It would also be a powerful political tool of the Australian government and its people, a benevolent and welcome help in a region where many Australian aid efforts are treated suspiciously. It would also establish a non-threatening Australian "presence", one that is ongoing and on the spot.
There is another argument that you could scale down the ship to 3000t, a bit larger than the
Leeuwin-class survey vessels, with a corresponding smaller medical/health team that can still undertake clinics and medical procedures. But you could have three smaller vessels over one larger one and visit more places with greater frequency. Australia would be three times as visible, and with three times the eyes.
I would never advocate that such a vessel and its officers and crew become agents of Australian intelligence because if it ever came out it would be incredibly damaging, but by meeting regional leaders and the people, it is inevitable that they would have an excellent understanding of what was happening in these communities.
Such a vessel/s would be on hand and already equipped to be tasked to emergencies and disasters, and they needn't cost a fortune to run (even if the ADF had to go alone on costs and crew).
It is important for the ship in the role to be an Australian ship, and not just government chartered like the
Aurora Australis and the capability contracted to private enterprise (like RAAF SAR). Although the primary purpose is to provide an altruistic medical service, much of the return value to Australia is in the seeing that it is Australian. But the potential pay back could be enormous in just goodwill alone generated by regular visits by an Australian medical ship, let alone the political, social and health benefits.