In a scene in Black Panther: Wakanda Forever, the Americans were on an offshore platform, using the underwater vibranium detector to search for vibranium. It is my understanding that:
They only had the one vibranium detector, built by Riri Williams, and had no way of building more,
The detector looked like it had a fairly short range, having to be underwater very close to the vibranium to set it off, and
Prior to using the detector, the Americans had no information about where vibranium could be found, other than Wakanda.
Given the above facts, how did the Americans know where to set up their platform? Did they send their one vibranium detector all the way around all of Earth's oceans until they found the one spot that had vibranium? Or is there something I'm missing here — are any of (1–3) above false?