Gulf of OmanUS cannon fire disabled Iran’s M/T Hasna.
USS Abraham Lincoln’s F/A-18 fired 20mm rounds after Hasna’s crew ignored warnings — the blockade’s 2nd kinetic enforcement since April 13.
US military figures show 52 ships redirected since the blockade began; Iran has not commented as nuclear talks continue.
Sources: New York Post, Hindustan Times, The Jerusalem Post, B92, CNA
WHAT A BLOCKADE LEGALLY IS
Under customary international law, a blockade is an act of war. The 1909 London Declaration and the 1994 San Remo Manual codified the rules: it must be declared, notified to neutrals, applied impartially, and effective. Calling an interdiction campaign anything other than a blockade is usually a deliberate legal hedge — naming it triggers belligerent rights and obligations on both sides.
THE 20MM CHOICE
An F/A-18's M61 Vulcan fires 20mm rounds at 6,000 per minute. Used against a tanker hull, it's a disabling weapon — designed to puncture engineering spaces and steering gear without sinking the ship or igniting cargo. The choice signals enforcement, not destruction; a missile would have been the opposite signal.
THE GEOGRAPHY
The Gulf of Oman sits outside the Strait of Hormuz, in international waters where the US Fifth Fleet operates routinely. Interdicting here — rather than inside the Strait — keeps the action in waters where transit-passage law is uncontested and avoids triggering Iran's claim that Hormuz is governed by Iranian domestic law.
THE TANKER WAR PRECEDENT
From 1984 to 1988, Iran and Iraq attacked over 450 commercial ships in the Gulf. The US response — Operation Earnest Will — reflagged Kuwaiti tankers under the American flag and escorted them. The current pattern inverts that posture: the US is now the interdictor, not the protector, and Iranian-flagged hulls are the targets rather than the threat.
WHY OIL DIDN'T BREAK
Brent's muted reaction to interdictions tells you the market reads this as enforcement against specific cargoes, not closure of the lane. Closure prices in within hours; selective interdiction prices in over weeks via insurance premiums at Lloyd's, not the spot benchmark.
THE INSURANCE CHOKEPOINT
Lloyd's of London war-risk premiums — not the kinetic events themselves — close shipping lanes. A single interdiction adds basis points; a pattern of them adds percentage points to hull value per voyage. At a certain premium, owners reroute regardless of whether any ship has actually been hit.