OK, so like here's the dill, hey: They said that when they had the signal for two hours the other day, the signal got stronger and stronger then faded as they went past it, which they said was to be expected. If that's the case, they need to pinpoint where they were when the signal was the strongest and draw a line perpendicular to the course of the ship at that time. Whatever was pinging is on that line somewhere; it shouldn't be too hard to check out with their automagic robot diver dilly. If the Toad Pinger Locater dill has any directional faculty at all and can tell them port or starboard, it will be even easier.
They still won't find the plane, it's in Turkmenistan, but they will find whatever was pinging.