You may well be right about that Derek. I was on board HMAS Bundaberg in Cairns, just before she left for Sydney to take part in the International Fleet Review, and spoke to several crew members. They told me that the Armidales were being worked beyond their original design specifications. Their official navy designation is ACPB, Australian Coastal Patrol Boat but, as most people would know, they have spent a lot of their sea time in mid-ocean chasing people smugglers, in all sorts of weather. It may well be that the design criteria were incorrect, but I have no way of knowing what that criteria is. The fact remains that they are suffering from overwork, for whatever reason, and cracks are appearing in the hulls. Perhaps aluminium was not the right material to use for such a vessel, but the builders, Austal, have a lot of experience building boats using that metal, including patrol boats for other countries.
As a class I believe that they are well liked by their crews, and are apparently good sea boats, plus they look good.
BTW, the boat shown in the photo above is ACPB 84, HMAS Larrakia.
Peter.