Originally Posted by gonebutnotforgotten
... if these pings came from the searching ship(s), why did they disappear, roughly at a time when the original locator batteries were expected to die?
The #3 and #4 ping detections were dismissed some time ago as not being related.
#1 ping detection apparently occurred as the TPL was in the process of being lowered, I think around the 250 ~ 300m mark and while the vessel was moving slowly ~0.5 knots. The detection was lost after 2h 40m, and it is possible that if the source was on the Ocean Shield, that could be an explanation if the tow catenary had lengthened to beyond the detection range.
#2 ping detection was 7.16NM by 205°T from the initial #1 ping and about 5 hours later as the vessel was returning on a reciprocal track, but only for a short duration. The timer on the ship's bar door had started! Think of any other explanation?
#2 ping location was the center of the 10km radius on which the Bluefin-21 search grid was based. JACC's reference to the search being centered on the 2nd ping detection of 8 April was not correct.