Transit or no transit – that’s the question
ince 13 April, the challenge for vessels to enter or leave the Middle East Gulf has been complicated significantly. While in the first 1.5 months of the conflict the full focus was on the Strait of Hormuz, the targeted US blockade on Iranian or Iran-related vessels is geographically much less specific.
Accordingly, we have to differentiate two distinct and operationally independent blockades:
• Iranian de facto closure of the Strait of Hormuz enforced by the IRGC since 28 February,
• A US naval blockade of Iranian ports initiated by CENTCOM on 13 April, which is not necessarily implemented close to Iranian ports nor within the Strait of Hormuz, but flexibly around an area about 300miles to the West between the Pakistani/Iranian border and the most eastern “corner” of Oman.
These two instruments target different actors, operate under different legal frameworks, and have different geographic reach. And there is no linkage between the passage of the two blockades. In fact, individual vessels will likely face challenges either
• with the passage of the Strait of Hormuz (non-Iranian vessels or no agreement with Iran – in that case the US blockade is unlikely to apply)
• Or with the US blockade (for Iranian vessels or vessels with close ties/agreements with the Iranian side – in that case the Strait of Hormuz is unlikely to be the challenge)
Understanding this distinction is now the single most important analytical lens for tracking flows, Gulf export disruption, and the prospects for physical market recovery.
Map shows passages through the US blockade (updated April 20)
Vortexa has observed the following on the water activity for energy tankers related to the US Naval Blockade, focussing solely on sanctioned tankers and those with Iranian links (loaded from Iranian ports currently or in recent months) (all other tankers from the eastern part of the UAE or Oman are supposedly free to pass).
→ 34 energy tankers with Iranian links transited the area (inbound and outbound) (April 13 – April 21)
→ 6 dark outbound transits were carrying 10.7mn barrels of Iranian crude (April 13 – April 21), as of April 22, 3 have reportedly been interdicted by the US
→ All crude carriers have transited with AIS disabled
Passages via the Strait of Hormuz
In parallel to the US naval blockade, passages through the Strait of Hormuz have not collapsed outright, but have instead shifted into a more selectively constrained transit environment.
On average, 4.5 transits per day were observed between April 13-21, compared to 4 transits per day in the preceding 30 days – indicating that baseline throughput has been broadly maintained, despite heightened tensions. However, since the introduction of the US blockade, Iran-linked activity has declined with 1-2 tankers per day transiting the Strait of Hormuz between April 13-21, compared to 2-3 per day in the preceding 30 day period.
Recent events suggest that enforcement has become more kinetic and selective, with Iran targeting vessels attempting to exit the Strait without alignment or authorization. Importantly, this dynamic is not universally applied:
→ Non-Iranian vessels without agreement are increasingly challenged at the Strait
→ Iranian-linked vessels, by contrast are more likely to face risk further downstream within the US blockade environment, not at the Strait of Hormuz
Impact on Iranian crude production, storage and flows
While causing widespread media attention, from a fundamental point of view the US blockade is unlikely to have any meaningful effect on Iranian crude supply to the market in the medium term (2-3 months).
Concerning seaborne crude imports, this is because about 160mb of Iranian crude are on the water, 130mb of which are already outside the US blockade area. This is sufficient to supply about 2.5 months of typical Chinese import needs, and more vessels are likely to trickle through the US net.
Iranian crude/condensate on the water (b) (April data includes days 1-21)
And Iranian oil production is unlikely to be immediately constrained because it would take 22 days for Iran to reach its maximum observed fill level since 2020, if it stores 1.5 mbd of crude production in storage tanks. And even more important, ballast tanker supply may be sufficient to sustain production for up to two months in total, albeit precautionary production curtailment is likely earlier. But again these figures are for a case where the US blockade hinders 100% of the Iranian oil traffic, which appears unlikely on the initial indications.
Middle Eastern crude/condensate onshore inventories by country (mb)
Vortexa’s latest release utilising proprietary waypoints and regions allows clients to identify which vessels have attempted to navigate which blockade, whether they are located inside or outside both blockades or right in-between, cutting through speculation with data you can act on.
By aligning specialised data, agile product development, and industry expertise, we’re helping traders and analysts move from speculation to defensible decision-making.
hellenicshippingnews…