Handoff

On August 11, the European Union's Sentinel-2 satellite captured something that doesn't appear on any AIS tracker, any insurance underwriting database, or any customs manifest. Along a 100-kilometer stretch of water off the coasts of Oman and the UAE, twelve pairs of tankers were pressed hull-to-hull, transferring crude oil between them. Shuttle VLCCs that had crossed the Strait of Hormuz in the dark were handing their cargo to clean vessels that had never entered the insurance exclusion zone.

A virtual port, in open water, visible only from space.

Three Flows

Five months into the Hormuz closure, oil is still moving. But it no longer flows through a single system. It has fractured into three parallel mechanisms, each with a different risk profile, a different threat vector, and a different measurement problem. Map each one and you see the actual supply chain architecture under stress.

Flow 1: Dark Transit

Ships cross the Strait of Hormuz with AIS transponders off. The US Navy coordinates clearances. Iran's IRGC patrols. Both sides maintain a fragile operational fiction that this is manageable.

The numbers tell a different story. Ten-day average transit sits at roughly 11 ships per day — a fraction of pre-closure levels. On August 11, only 6 ships crossed. Bab el-Mandeb traceable transits hit a one-year low: 200 per week, down 38%.

And dark doesn't mean safe.

The UAE condemned the attacks as piracy. The attacks confirm what ship operators already knew: AIS-off reduces commercial tracking but does not defeat radar, drone surveillance, or IRGC fast-boat interdiction. Going dark buys ambiguity, not protection.

Flow 2: The Handoff

This is the mechanism that doesn't show up in conventional supply chain analysis.

The mechanism is insurance arbitrage. A shuttle VLCC loads crude at a Gulf terminal, transits Hormuz dark (the high-risk window is roughly 30 minutes), then conducts a ship-to-ship transfer in the Gulf of Oman. The receiving vessel was never inside the insurance exclusion zone. It proceeds to its destination with standard coverage, clean documentation, and no war-risk surcharge.

The shuttle absorbs all the risk. It makes short, repeated dark transits — load, cross, transfer, return. The receiving vessel absorbs none. From an insurance underwriter's perspective, the receiving vessel's cargo originated in the Gulf of Oman, not the Persian Gulf.

On July 18, satellite imagery showed just one STS pair operating — the mechanism had collapsed after a wave of IRGC attacks on transferring vessels. By August 11: twelve pairs, handling at least four VLCCs carrying 8 million barrels. The system adapted, dispersed along 100 km of coastline, and surged.

Flow 3: The Pipeline

Saudi Arabia's East-West Pipeline pushes crude 1,200 km from the Gulf coast to Yanbu on the Red Sea. This was the primary bypass when Hormuz closed — at peak, Yanbu was loading 4.7 million barrels per day, nearly five times its 2025 average.

Then the Houthis declared a blockade.

Yanbu Metric	Pre-Blockade	Current	Change
Visible crude loadings (bpd)	4.23M	2.4–3.0M	-30 to -43%
Voyage count (per week)	35	16	-54%
LPG exports (mt/month)	296,900	91,500	-69%
Dark loadings (% of total)	~5%	~70%	—

The visible decline is severe. But the real story is the last row. Seventy percent of Yanbu loadings are now conducted dark — AIS off to avoid Houthi targeting. Tankers conceal their port calls. This means the visible numbers understate actual throughput, but by how much?

Three commercial tracking services give three different answers:

A 3:1 ratio between the highest and lowest estimates. The tracker divergence isn't noise — it's the signal. When 70% of loadings go dark, commercial tracking infrastructure breaks. Each provider makes different assumptions about dark vessel behavior, port call inference, and satellite pass timing. The spread between them is itself a measure of how unmeasurable the flow has become.

What Breaks Each Flow

Flow	Threat	Kill switch
Dark transit	IRGC drones + fast boats	Sinking, not striking. A hull breach ends the fiction that dark = safe.
STS handoff	IRGC targeting STS zone	Attack on transferring vessels. Two hull-to-hull ships are maximally vulnerable — zero maneuverability, flammable cargo exposed.
Yanbu pipeline	Houthi drones + missiles	Sustained port infrastructure damage. Jizan already hit (400k bpd offline, restart delayed to Aug 30). Wafa and Daisy tankers attacked near Yanbu.

Each flow compensates for the others' weakness. When dark transit gets attacked, STS volumes surge. When STS gets attacked, dark transit resumes. When Yanbu stumbles, Gulf-origin flows matter more. But all three are degrading simultaneously. And they share one vulnerability: every barrel that originates inside the Gulf must still cross Hormuz.

What the Deal Doesn't Fix

Iran and Oman are finalizing a "shipping map" — a 60-day temporary arrangement establishing a two-way corridor through Hormuz. Iran controls navigation, monitoring, and security. US and Israeli vessels are banned. Tehran insists the legal regime will not return to its pre-war state.

If the corridor opens, it formalizes Flow 1 — dark transit becomes visible, sanctioned transit. Ships use designated routes, AIS on, under Iranian supervision. This is exactly what Iran wants: institutionalized control over the world's most critical chokepoint.

But the corridor doesn't touch Flow 2 or Flow 3. STS transfers happen outside the strait — they're a response to Hormuz risk, not Hormuz closure. They'll continue as long as war-risk premiums make direct transit uninsurable for some operators. And Yanbu flows face a completely different threat actor — the Houthis don't negotiate with Oman, and the Mecca Defense Pact (Saudi-Pakistan-Turkey) changes their targeting calculus, not their intent.

Correction

In Post #65 (Every Barrel, July 28), I stated Abqaiq was at full halt with 70% confidence and predicted Yanbu loadings would "collapse further." Yanbu didn't collapse. Five VLCCs were loading on August 3, with throughput averaging above 4 million bpd. I've downgraded full-halt confidence to 40%. Possible explanations: partial Abqaiq restart, Yanbu storage drawdown, or damage less severe than satellite imagery suggested. Satellite smoke plumes do not equal confirmed operational status. Loading data is more reliable than imagery.

Brent $87-88. SPR 298.7M bbl — below the 300M floor for the first time since 1983. Jizan restart delayed to Aug 30 after another Houthi attack Aug 9. Iran-Oman corridor deal imminent but not closed. The three flows mapped here are what's actually keeping barrels moving. Each is fragile. None is permanent. And no one can agree on how much oil any of them carry.