Hormuz Delays Raise Corrosion Risk for Sulfur Bulkers

Hormuz Congestion Turns Into a Structural Risk

The Gulf region remains one of the world’s leading sources of raw elemental sulfur, a byproduct of processing sulfur-heavy oil and gas that is routinely loaded onto bulk carriers for export to industrial buyers of sulfuric acid. According to a report by The Maritime Executive, citing maritime consultancy Brookes Bell, the ongoing Strait of Hormuz crisis has left a number of these sulfur-carrying bulkers stranded in the Gulf far longer than is safe, raising the risk of aggressive corrosion inside their cargo holds.

Brookes Bell’s head of non-destructive testing, Arron Jackaman, is urging owners and insurers to inspect any bulker that has been sitting in the region’s hot, humid conditions with sulfur cargo over roughly the past two months. He notes that earlier inspection generally means less damage and lower repair bills, since remediation frequently involves cutting out and renewing hold plating.

Why Limewash Coatings Have a Shelf Life

Safe carriage of sulfur normally starts with cleaning the hold of previous cargo residue and applying a limewash barrier coating. The lime is meant to neutralize the sulfuric acid that forms naturally when sulfur combines with moisture, slowing corrosion without fully stopping it. That protection is generally rated for around 20 days; beyond that window, corrosion accelerates sharply.

Once moisture and sulfur interact, an acidic environment develops that converts steel into iron sulfide at a pace considerably faster and more destructive than typical saltwater corrosion. Vendor RBM has previously linked sulfur-driven corrosion to cases where vessels were written off entirely.

Vessels Stuck Three Times Longer Than Safe Limits

According to Brookes Bell, some ships held up by the Hormuz situation have now exceeded the rated protective life of their limewash coating by roughly three times over. Jackaman put it bluntly: that protective barrier has effectively been used up. His firm has documented pitting as deep as a quarter of an inch after only about 50 days of exposure — wastage severe enough to eat into the sacrificial corrosion allowances that IACS’ Common Structural Rules set for tank top plating, bulkhead stools, and sloping hopper plating.

Visual Inspection Alone Can Mislead

Jackaman cautions that the visible severity of sulfur pitting can overstate the real structural impact, meaning a purely visual survey risks inaccurate conclusions. Pitting tends to cluster where cargo grab equipment has damaged the coating, and on tank top plating that is left uncoated by design as a matter of routine practice. Without proper quantitative measurement, he warns, steel that actually remains within class limits could be condemned unnecessarily — an outcome that adds unwarranted cost and downtime for owners.

What This Means for Owners and Charterers

This situation illustrates how a geopolitical chokepoint disruption can translate directly into a hidden structural liability. Vessels delayed for reasons entirely outside their control — congestion, war-risk routing, or holding patterns near Hormuz — can quietly accumulate corrosion damage that isn’t apparent until a hold inspection or drydocking reveals it. For owners and managers with bulkers that spent extended time in the Gulf carrying sulfur, the practical takeaway is not to wait for a scheduled survey cycle. Targeted, quantitative hold inspections using thickness gauging and non-destructive testing — rather than a visual once-over — are essential to separate genuine structural wastage from cosmetic pitting, and to avoid either underestimating a real safety issue or over-condemning sound steel. Charterers and insurers evaluating these vessels for the next voyage should likewise treat time spent at anchor in the Gulf as a data point worth requesting alongside cargo documentation, since the corrosion clock on limewash protection keeps running whether or not a vessel is actually discharging.

As chokepoint disruptions persist, this case is a reminder that delays don’t just cost time and freight — they can leave a lasting mark on a ship’s structural integrity that only a proper survey will reveal.

Reviewed by Ibrahim Halil Ceylan, Marine Surveyor at Apeks Marine.