That works. I'm really happy this topic is back in play, I've been interested in a solution for about 5 years now (I guess I should just try some development on it myself if I am impatient)
The key requirements for a solution, from my perspective, are:
1. Acknowledgement (or Silence) must be persistent, meaning it lasts for the duration specified even if the target goes outside the alarm
limit then comes back in. (this could be accomplished if acknowledgments are recorded in the AIS Target list; if that MMSI has had an acknowledgement previously then honor it).
2. Acknowledgments must be applicable even when the alarm is no longer sounding (many alarms are so transient that the user has insufficient time to hit the acknowledgment button) the addition of this on the AIS right click menu would do that.
3. It would be helpful to be able to do it from the AIS list because, in a area with many targets, once the alarm stops you might not know which AIS target caused the alarm nor which to click on to prevent further ones. On the AIS List, if you could see for each target on the list how many alarms you had received, then you could know which one to acknowledge.
BTW, I never have figured out the difference, operationally, between acknowledge and silence.