Maritime Defense Weekly: Energy Flows and Infrastructure Risk

Week in Focus

• A Russian diesel cargo is signaling arrival in Cuba following AIS destination changes and offshore ship-to-ship loading.
• A Baltic subsea power cable shutdown coincided with vessel behavior matching prior infrastructure exposure indicators.
• U.S.-Iran escalation rhetoric included explicit reference to potential disruption of commercial flows in the Strait of Hormuz.

Russian Diesel Cargo Signaling Arrival in Cuba

A Hong Kong-flagged medium-range tanker is signaling arrival in Cuba on March 2 after multiple AIS destination revisions. The vessel initially broadcast Havana, then shifted to “Caribbean Sea,” and later to “Gibraltar for orders,” despite already transiting the strait.

Windward’s assessment indicates the tanker likely loaded through a ship-to-ship transfer offshore near Cyprus during a temporary AIS blackout. Draft data show an increase several days after departure from the Black Sea transfer zone, consistent with floating storage and transfer of Russian middle distillates.

If confirmed, this would be the first refined products cargo arrival in Cuba since early January. The movement follows a January 29 executive order authorizing tariffs on imports from countries supplying oil to Cuba. Recent regional shipping behavior reflects disruption pressure, including cargo diversions, aborted loadings, and route reversals. 

The vessel is not sanctioned and has not previously called at a Cuban port. However, AIS draft changes and temporary transmission gaps during the loading window reinforce the likelihood of offshore transfer activity rather than a conventional port loading.

Baltic Subsea Infrastructure SwePol Cable Shutdown

On 11 February 2026, the SwePol high-voltage subsea cable between Poland and Sweden was taken offline following a reported technical fault. Operators stated there is no evidence of deliberate interference.

Windward MIOC identified a large Liberian-flagged tanker operating directly over the cable corridor in the days preceding the shutdown. The vessel conducted two course deviations and a 24-hour anchoring event above the corridor before switching off AIS within the Russian EEZ. SAR imagery from the incident window detected a similarly sized non-transmitting vessel in the area.

Individually, these indicators are not conclusive. Combined, large-hull presence above infrastructure, extended anchoring, and AIS gaps align with previously observed Baltic subsea exposure patterns. No attribution has been established.

The convergence of corridor anchoring, route deviation, and AIS loss during the incident window elevates monitoring thresholds for subsea infrastructure corridors in contested waters.

Strait of Hormuz Shipping Risk

Iran temporarily closed parts of the Strait of Hormuz this week during a live-fire military drill described as “Smart Control of the Strait of Hormuz.” Semi-official outlets reported missile launches into the waterway, and mariners were warned by radio of planned surface firing.

The Strait is approximately 21 miles wide at its narrowest point and carries roughly 20% of globally traded oil. While alternative pipeline routes exist in Saudi Arabia and the UAE, most volumes transiting the Strait have no alternative exit from the Gulf.

Although Iran has previously harassed shipping in the waterway, full closure is rare and has not been sustained in modern escalation cycles. The extent and duration of the shutdown were limited, reportedly lasting several hours, and there are no confirmed prolonged disruptions to transit.

The drill occurred amid heightened U.S.-Iran tensions and forward deployment of U.S. carrier strike groups in the region. Public escalation scenarios have included explicit reference to disrupting commercial flows through the Strait and targeting shipping in the Gulf as a pressure mechanism.

Brent crude rose approximately 10% as markets priced in potential supply disruption risk.

There are no confirmed operational interdictions of commercial traffic at this time. However, the temporary closure and live-fire activity represent a clear signal that maritime transit remains embedded in the escalation calculus.

The temporary restriction, even if limited in duration, demonstrates operational capability to interfere with one of the world’s most critical maritime chokepoints.