Straits of Hormuz, not international watersIran has joint sovereignty with Oman, UAE and Iran. Iran can legally block their portion of it. The deepest part needed fir deep draft ships like oil tankers. In other words Saudi can ship squat if Iran doesn't let them. "The Strait of Hormuz is not international waters. Hormuz is an international strait covered by the territorial waters of Iran and Oman (see Gioia). The coastal states have sovereignty in the territorial sea."
https://simple.m.wikipedia.org/wiki/Strait_of_Hormuz#:~:text=The%20Strait%20of%20Hormuz%20is,Musandam%2C%20an%20exclave%20of%20Oman.&text=The%20strait%20at%20its%20narrowest,miles%20(39%20km)%20wide.