You’re delusional. Anyplace in the PG is within helo range in minutes of a tanker attack. “Under surveillance” my ass. If a tanker is attacked anywhere in the PG, in less then one minute a helo will be airborne from one of our many USN warships to get photos.
As far as the ordnance, the Iranians invented and deployed their own advanced anti-armor mines to use against our forces in Iraq. They are NOT stupid, and are not idiot client vassals (like the Saudis). The Iranians are 100% able to develop and deploy their own anti-ship mines, as well as Swimmer Delivery Vehicles, bubble-less SCUBA for frogmen, etc etc.
Leaving aside how quickly the US Navy can get on scene anywhere in the Persian Gulf for the moment...are you absolutely certain the video was taken after the oil tanker was attacked and not before?
If true, that would support the idea that the Iranian vessel was simply responding to the attack as opposed to being caught in the act of perpetrating it.