The idea is double hull, as in, not easily sinkable, which COULD block the strait.
Stage a few old tankers on either side of the straight to run interference for the convoys as they enter/exit the Gulf.
Could probably improvise some platforms and a crude hangar deck for ASW helo’s. Of course most of this stuff would have to be done in advance as the missile shooting phase would probably stop with days as I’d expect the Army & Marines to land significant assets to hunt the launchers.
There’s also a few restive provinces in that area of Iran that would probably take the opportunity to string-up some mullahs. There are significant No-Go areas for the Khameni regime.
An illuminating series of reports (too bad the shoe maker didn’t pay close enough attention to the quality of his own shoes - STRATFOR got badly hacked over the past weekend, and is still ‘down for maintenance’):