The source is wrong on very basic details. And the big picture of the story is nonsensical:
1) this is a very very very secret operation that Congress shouldn't be informed about, but a shitton of services - including foreign countries - were involved
2) they laid the mines during... A very public and documented military exercise. They certainly couldn't do it from a nondescript modified fishing vessel, no, they had to make it obvious it was them. But very very very secret operation indeed.
This is just an idiot's idea of a secret military operation.
These errors largely sound like obfuscation... like a potentially true narrative with the names and places changed:
- Instead of revealing the fishing vessel, he describes a vessel that it couldn't have been.
- Giving the real timing would expose the vessel, so he gives timing that wouldn't have worked as a placeholder.
- Too many people were involved, because only a subset were actually involved - or maybe even just an analogous group.
Hersh eliminates the intelligence value by obfuscating exactly who did what and how, but provides lay readers (to whom the specific details don't matter) a story that conveys a general sense of how the mission was achieved.
This is just an idiot's idea of a secret military operation.