US Marines began physically boarding vessels on 16 July to enforce the naval blockade CENTCOM reimposed on Iranian ports two days earlier, a harder posture than the redirect-only enforcement of the spring blockade.1
A redirect turns a ship away; a boarding puts armed personnel on a foreign-flagged deck to search it. In the blockade's first three days CENTCOM redirected four commercial vessels, disabled one and boarded one, according to The War Zone, its first public enforcement tally since the closure returned.2 The original April-to-June blockade redirected more than 140 vessels and disabled nine across a full 66-day run, so the new operation's three-day pace runs proportionally faster.
CENTCOM separately confirmed a Marine verification boarding of the sanctioned tanker Wen Yao, sailing under the alias Lan Jing, in the Gulf of Oman on 16 July.3 The rename is the evasion; the boarding is the answer to it. A tanker that changes its name to slip a sanctions list still has to carry its cargo past a warship.
Boarding commercial shipping is exactly the act the IRGC (Islamic Revolutionary Guard Corps) has used to justify its own seizures, including the two supertankers it disabled in Omani waters on 14 July. Iran and several shipping bodies argue the blockade breaches transit-passage rights protected under the UN Convention on the Law of the Sea; Washington maintains its remit covers only Iranian-port traffic. Each armed boarding hands Tehran a fresh grievance while tightening the sea lane.
