Since the US blockade of the Strait of Hormuz began on Monday, the US military has stopped at least eight oil tankers from entering or departing Iranian ports. According to a Wall Street Journal article, US naval troops communicated with the crew by radio and told them to change course in every instance.
The Journal, citing officials, stated that no boardings were required since tankers followed the orders in every case.
US Marines stopped eight tankers, including the US-sanctioned Rich Starry, which was owned by Shanghai Xuanrun Shipping Co. in China.

According to reports, the US has sent thousands of US soldiers, including Marines and special operations teams, along with more than 15 warships to impose the blockade of Iranian ports.
The Hormuz Blockade by the United States
Tehran has been transporting its commodities and oil freely through the small strait since the start of the Iranian conflict, while severely restricting seaborne traffic from other countries, particularly those the Islamic Republic considers hostile.
Trump gave the order for US forces to block the Iranian ports at Hormuz after ceasefire negotiations with Iran broke down this weekend. The US military now intends to locate any Iranian vessel that crosses the Strait and, if need, personally board it.

A blockade of Iranian ports has been fully imposed as US forces retain naval superiority in the Middle East, according to a statement from the US Central Command (CENTCOM).An estimated 90% of Iran's economy is derived from maritime foreign trade. US forces have fully stopped economic trade into and out of Iran by sea in less than 36 hours since the blockade was put into place.
US Mines in Hormuz Are Being Cleared
Additionally, according to US forces, two naval guided-missile destroyers are undertaking operations in an effort to remove mines that Iran claims are in the strait.Iran is unable to locate the mines it placed in the Hormuz and lacks the means to remove the explosives, which keeps Iran from permitting additional traffic to pass through the strait, according to an earlier story in the New York Times.
One of the main demands of the United States to end the war in Iran is the opening of the Hormuz, a chokepoint for a fifth of the world's oil supply. Fuel prices skyrocketed as a result of the strait's virtual closure, causing the biggest energy crisis in decades and placing pressure on Donald Trump at home.