Todjaeger
Potstirrer
A system like Praire-Masker could also make it harder to target one of the FFH's as well. What I am not so certain of though is whether it is better to have advanced countermeasures for use vs. inbound torpedoes, or if it better to have more capable sonar systems to attempt to detect a sub prior to it firing torpedoes.The most danger to HMNZS Te Mana off N. Korea is a replay of the Cheonan trap. Queued up by allied ASW assets an NZ Seasprite could potentially drop a depth charge on the midget sub or shoot Maverick/Penguin at the sub tender while the FFH remains at stand off range. Te Mana will be staying as far as possible out of the known range of N. Korea's acoustic homing CHT-02D torpedo, so it can't chase subs with its hull mounted sonar. The Anzac's really need fitting with something equivalent to Sea Sentor, sort of underwater chaff as fitted to the RN's bombers and T45's.
Particularly since the RNZN does not currently have much in the way of ASW assets (especially for an island/archipelago nation). At present the ASW sensors available to the NZDF amount to the hull-mounted sonars of the FFH's and the MAD and sonobuoys dropped from the P-3K Orions. AFAIK sonar systems which are hull-mounted on surface vessels are not as effective as a towed sonar array, at least not passively. Also, a friend of mine (ex-USN served on a Los Angeles-class SSN his entire tour) is rather dismissive of an Orion's ability to detect a sub...
That leaves me wondering if a Kiwi vessel might not know a hostile sub was present until moments before a torpedoe would impact. This also ties in with the Cheonan incident in that even if a vessel does have a torpedoe countermeasure, the vessel would still need sufficient time to deploy the countermeasure. From what I recall of what happened with the South Korean vessel, even the survivors could not tell for certain if she had been fired upon with a torpedoe, suggesting the time between torpedoe launch and impact was so short the torpedoe was not detected. This in turn suggests that unless a countermeasure was already deployed, one would have been of little use.
-Cheers