Rather enjoyed this. It's not "Master and Commander" or "Das Boot", but as seagoing adventures go it is quite enjoyable. It is set in Northern Australia's tropical border waters aboard a patrol boat guarding that border against illegal fishers, smugglers of various cargo, people smugglers and terrorists. And because the Australian Navy lent a few boats and crew, it is actually good in the props and terminology department (although it has been dumbed down in places: Do the RAN use left/right in place of port/starboard, for ex.?)
Like with all series, there are weak episodes and some very strong ones, and it's not necessarily those that involve the leading characters. Series 4 in particular has a number of dramatically very good stories. It was also the only one that did not have an overall story arc/theme.