On the floor?
#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?
I always thought the plane was floating at a great depth and drifting south at about 1 kt which accounted for the long first encounter.
Pings 3 and 4 killed that theory.