The OP is confusing two incidents. A US ship was not boarded or taken to an Iranian port. It was intercepted while passing through the straights which are Iranian waters. It was "escorted" without incident through the straight. The ship that was boarded and escorted to an Iranian port was not a US flagged ship. An additional link to the incident is not needed. The one in the OP explains everything. It just needs to be read.
how are the straits "IRANIAN WATERS"??? do they go THRU Iran?----they are not considered international waters?
No, the Straits if Hormuz are not international waters. It is shared by Oman and Iran. Passage through the straits are done under United Nations and international agreements. Shipping lanes are strictly defined and any variation or mistake affords either nation to take the same action any other nation is allowed to take when it's territorial waters are violated.