Really good to have you back Gary, your input has been missed.
My take on smaller PBs is that they work best in busier waters in more populated regions where there is plenty of infrastructure and the ability to deploy multiple craft covering a range of missions. Whether they are operated by the RAN, Customs, police or some other agency doesn't really matter, in fact the only reason I could see for the RAN having them is if we decide to develop an expeditionary capability.
For more remote areas larger, more autonomous vessels are the way to go. To start with they have the range and endurance to permit them without having to rely on shore based infrastructure but ideally also large enough to be able launch and support boarding and landing parties. One of the key requirements of the Fremantle class replacements was that they be able to operate two RHIBs and one of the biggest regrets was that a UAV or helicopter capability wasn't specified, this is the stuff of a large vessel, not a small one.
As for a mother ship for EEZ patrol I would rather see a class of OPVs, corvettes or sloops able to operate not just a pair of RHIBs but combat boats or fast interceptor craft launched from a rear ramp and stowed on / in a multi mission deck, rather than a larger vessel with a floodable dock or multiple davits. A combat boat or fast interceptor craft could be small enough for an OPV etc. to operate a pair of but large enough to conduct independent operations away for a couple of days. These boats could deploy up rivers, into shallow deltas, wet season waterways, drop off landing parties, set up OPs etc. extending the reach of the larger combatant. They could even be used in conjunction with the larger vessel to cut off or intercept fleeing illegal fishers or smugglers. Through in a helicopter and the capability increases exponentially, same with UAVs etc.
To me, rather than a dedicated mother ship with multiple PBs you would be better off with a dozen or more OPVs, corvettes, sloops, each with a pair of PBs, combat boats, or interceptors plus helicopter facilities. If you look back in time the the RN then RAN used small (often obsolete) cruisers for the role, primarily because of the lack of supporting infrastructure, this is just returning to how it used to be done.
