The Strait Learns to Whisper
Published 4 October 2026
Closing a strait is mostly a matter of persuading people not to enter it. Nobody had to sink the whole of Hormuz. It was enough that insurers, crews and charterers started doing their sums.
Four tankers
On 1 March, according to Vortexa data cited by Reuters, four crude tankers transited Hormuz. The average from January onward had been 24 a day. Three of the four were Iran-flagged. The figure counts crude tankers, not all vessels, and it is one day. Even so, it was a long way from normal. Reuters reported the strait effectively shut for a fourth day by 3 March, in its global energy roundup. "Effectively shut" is the reporter's phrase for what traffic was doing, not a legal declaration that guaranteed zero crossings.
The Gulf's production switches
The same roundup records the knock-on effects. Qatar halted LNG production. Saudi Arabia suspended its largest domestic refinery. Iraq cut output. None of these required a missile to hit the plant in question: when exports cannot leave, storage fills, and a producer who cannot ship has to stop pumping. Reuters reported European gas up as much as 40% in a day, after a 40% rise the day before, and Brent futures settled at $81.40 on 3 March, up 4.7%, according to the pack of Reuters price reports this file draws on.
The paperwork of fear
War risk insurance is a seven-day arrangement that can be cancelled on short notice, and it was. On 2 March Reuters reported cancellation notices from Gard, Skuld, NorthStandard, London P&I and American Club, effective 5 March, in its report on marine insurers cancelling war risk cover. Buyback options could reinstate cover, so this was not a blanket absence of insurance. It was a repricing, announced with a deadline.
By 6 March, Reuters had the first numbers. Marsh estimated roughly 1% to 1.5% of vessel value for the extra cover, varying by exposure. Jefferies used a 3% example against a prewar hull premium of 0.25%. For a $250 million vessel, that is $7.5 million against $625,000, a rise of 1,100%. Gallagher said cover remained available. These are examples and estimates, not a market-wide tariff, and the later chapters on insurance keep the hull and cargo denominators apart.
What the first week established
Three things, all of which outlasted the first week. First, a strait does not have to be mined to be closed to commerce. Second, the cost of passage is a bundle: fuel, crew risk, insurance, delay. Third, the producers who cannot export suffer in a different way from the consumers who cannot import. A refinery in Saudi Arabia, a gas train in Qatar and a diesel buyer in Europe are three different victims of one choke point.
The next chapter leaves the water for the politics of a country that had just lost its supreme leader.
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