Sorry but this doesn't really answer my question. I know the sea is vast. Yet we are able to navigate it consistently. Why is this vessel unable to stay in contact with its parent and relay its relative location?
I'm not an expert, but I think this is an incorrect assumption. We can navigate it decently on the surface (even then, plenty of ships sink/go missing each year [1]) but underwater is a whole different story.
> Why is this vessel unable to stay in contact with its parent
That is kind of the big question here.
[1] https://en.wikipedia.org/wiki/List_of_shipwrecks_in_2022