Really we’re getting pretty into the weeds when we talk about repelling boardings...
What’s Iran’s strategic objective with threatening tanker traffic? I’m not sure. If they’re attempting to demonstrate the credibility of their threats to tanker traffic, they already succeeded. They’ve holed a couple, and they’ve pirated a couple, releasing one at their leisure, and keeping custody of one belonging to one of modern history’s pre-eminent maritime powers.
Can we stop them seizing tankers? With enough resources, definitely. Can we deny Iran access to the waters? With more resources and adequate maritime surveillance, also yes. But now that’s playing hardball, and if we choose to do that, so can they. Hardball for them means putting a Silkworm into the side of a tanker. Can we run missile interdiction in protection of all tanker traffic? Not a chance.
Which gets us back to: what is their objective and how far will they go to achieve it? Can we deny their objective AND protect and preserve tanker traffic through the strait? That I don’t know. I do feel reasonably sure that no matter how much we escalate militarily, they will probably have the ability to hard-kill a tanker long past the point where that particular factor remains significant in our political and diplomatic calculus.
I don’t know where that leaves us. Killing Iranians =/= stopping Iran.