| The heart of the Iran's arsenal is its 200 small potential-suicide boats ...
Back when I was in the Army, that is what we would have referred to as a target-rich environment. Swarming is possible, but I doubt that the U. S. Navy would allow itself to be blindsided by the Iranians. Considering the threats that have been made, I expect that Iranian ports and sea traffic are under surveillance, and any potential threats are being tracked.
The more significant threat comes from Iran's 23 submarines, but they aren't particularly quiet, and the Navy is petty good at Anti-Submarine Warfare.
Other posters have commented on the ability of the U. S. to retaliate via air power. The Iranian Air Force would not last long going toe-to-toe with the USAF/Navy/Marine air power that could be brought to bear. Iran's naval and nuclear infrastructure would be eradicated. Iran could respond asymmetrically through terrorist attacks, but they would be fighting outside their weight class. And remembering the U. S. response to 9/11, one should expect such attacks to result in an even more devastating blow on Iran.
The Iranians know all this. Why are they some bellicose?
One possibility is that the regime is under enough pressure that it is trying to look powerful for internal reasons. Another possibility is that they are trying to create the world crisis that would lead to the return of the 12th Imam. If it's the first, all is bluster, and we will have no war. If it's something like the second, ouch!