Growing Houthi Risk Amplifies Inefficiencies Across Tanker Trade Flows
The growing Houthi threat in the Red Sea and Gulf of Aden continues to amplify inefficiencies across global tanker trade flows, compounding the disruption already caused by the Strait of Hormuz crisis. Houthi forces have maintained a sustained campaign of attacks on commercial shipping since late 2023, and the tempo of attacks has increased in 2026 as the group exploits the broader regional instability. Clarksons estimates that Houthi risk is now adding approximately 12% to global tanker tonne-mile demand — a structural inefficiency that drives up freight rates, extends delivery times, and strains terminal capacity at ports along diversion routes.
For terminal operators and port security teams, the Houthi threat is not a distant conflict. It is an active, ongoing source of operational disruption that changes which vessels call at which ports, when they arrive, and what risk they carry.
How Are Houthi Attacks Affecting Tanker Routing?
The Bab el-Mandeb strait, which connects the Red Sea to the Gulf of Aden, has been effectively closed to most Western-operated tanker traffic since early 2024. Despite coalition naval patrols led by Operation Prosperity Guardian, the threat of anti-ship missiles, naval drones, and ballistic missiles has been sufficient to deter most tanker operators from transiting the strait.
The result is a mass diversion of tanker traffic around the Cape of Good Hope. Clarksons data shows that approximately 85% of tankers that would historically transit the Bab el-Mandeb are now routing via the Cape, adding 10 to 15 days to voyages between the Gulf and European markets. For tankers also avoiding Hormuz, the combined diversion can add 25 to 35 days to a round voyage.
What Is the Tonne-Mile Effect?
The tonne-mile effect is the single most important metric for understanding how route diversions affect the tanker market. When a VLCC carrying 2 million barrels of crude travels an additional 6,000 nautical miles via the Cape of Good Hope, it is occupied for approximately 15 additional days per voyage. Across the global VLCC fleet of roughly 900 vessels, even partial diversion rates create a significant absorption of capacity.
Clarksons calculates that the combined Hormuz and Houthi diversions are absorbing the equivalent of 12% of the global tanker fleet — meaning that 12% fewer vessel-days are available for productive cargo carrying. This tightness is the primary driver of elevated charter rates across VLCC, Suezmax, and Aframax segments.
How Does This Affect Terminal Operations?
Irregular arrival patterns. Vessels on Cape routing arrive at destination ports on schedules that differ significantly from historical norms. Berth planners who calibrated schedules based on Suez Canal transit times must now account for the longer voyage and its variability, which is affected by weather, bunker fuel availability, and port congestion along the diversion route.
Increased traffic at waypoint ports. Terminals along the Cape routing — including ports in South Africa, Mozambique, the Canary Islands, and West Africa — are handling increased tanker traffic that strains anchorage capacity, bunkering services, and port security resources. UKMTO has issued advisories for increased vessel density in several of these areas.
Elevated war risk on arriving vessels. Tankers that transited anywhere near the Houthi threat zone — even if they ultimately diverted — may have been exposed to targeting attempts. Pre-arrival screening should include review of the vessel's recent track for proximity to the Gulf of Aden and any reported incidents during the voyage.
Are Houthi Capabilities Increasing?
Intelligence assessments and UKMTO incident reports indicate that Houthi anti-shipping capabilities have continued to evolve. The group has demonstrated the ability to deploy anti-ship ballistic missiles, cruise missiles, naval drones, and aerial drones against commercial vessels. Targeting has become more precise, with recent attacks reportedly using commercial vessel AIS data to identify and track specific ships.
BIMCO has warned that the Houthi threat is likely to persist regardless of broader diplomatic developments in the region, as the group has demonstrated the independent capability and willingness to sustain attacks over an extended period.
What Should the Industry Expect?
The combination of Houthi risk and Hormuz disruption has created a new baseline for global tanker trade efficiency that is significantly worse than the pre-2024 norm. Even if one of these disruptions resolves, the other is likely to persist, meaning that some degree of route diversion and tonne-mile inefficiency will remain a feature of the market for the foreseeable future.
Conclusion
The growing Houthi risk is not a standalone disruption — it is a force multiplier that amplifies the inefficiencies created by the Hormuz crisis and other regional instability. For terminal operators, the practical effect is a sustained period of irregular scheduling, diverse vessel populations, and elevated risk profiles on arriving tankers. The ports that manage these inefficiencies most effectively will be those with flexible operations, robust risk screening, and the ability to adapt to a trade environment that has fundamentally changed.