Not forgetting the eight Cape Class vessels, the
Ocean Shield and
Thaiyak (stationed at Ashmore Reef) which are all armed with 50 cals. A 50 cal HMG is more than enough to shred a fishing boat.
Patrol vessels (abf.gov.au)
On top of this are the Cape Class being built as a contingency for the RAN (plus the two already in service with the RAN) pending the Arafura's coming on stream and the disposal of the ACPB. There will be a total of 16 Capes between Border Force and the RAN. If these are in good condition when no longer needed they may pass down to Border Force once the RAN focus on the Arafura (or they may remain in RAN service). As far as I can tell there is no formal indication of what the long term future of the Navy Capes.