IMCA highlights “unacceptably high” levels of fatalities and injuries from underwater ship husbandry, as vessel owners prepare for Strait of Hormuz reopening

• Demand for the cleaning, inspection, and maintenance of an estimated 600 vessels trapped in the Persian Gulf has risen sharply following Middle East peace deal
• Underwater ship husbandry is essential to maintain vessel efficiency and protect marine eco systems, but requires proper planning, competent personnel, and suitable equipment to safeguard divers, IMCA warns

The International Marine Contractors Association has reminded vessel owners and operators of the significant risks associated with underwater ship husbandry operations as activity in the Strait of Hormuz increases.

As vessels begin returning to service following extended periods at anchor, demand for hull cleaning, inspection, and maintenance has risen sharply. These activities, commonly grouped under UWSH, play a critical role in restoring vessel efficiency by removing marine growth and biofouling.

Bloomberg has reported that orders for crews to clean ship hulls fouled by algae, slime, and crustaceans have jumped more than 30-fold since US President Donald Trump announced an interim peace deal with Iran that will reopen the Strait of Hormuz.

About 600 vessels remain trapped in the Persian Gulf following the outbreak of conflict in the Middle East. With vessels having spent prolonged periods idle, the accumulation of marine growth on hulls is expected to be significant. This reduces fuel efficiency due to increased hydrodynamic drag, and also risks transferring invasive aquatic species between regions, damaging marine ecosystems.

However, UWSH remains one of the most hazardous areas of commercial diving. In recent years, IMCA has been made aware of multiple fatalities linked to UWSH. These incidents are frequently associated with unqualified or inexperienced dive teams and the use of inappropriate equipment, such as self-contained underwater breathing apparatus (SCUBA), rather than surface-supplied systems.

“Underwater ship husbandry continues to have one of the highest fatality rates in the diving industry,” said Bill Chilton, Diving Manager at IMCA. “Despite advances in technology and training, serious incidents and fatalities remain unacceptably high, particularly where operations are carried out without proper planning, competent personnel, or suitable equipment.”

To support the industry to mitigate the risks associated with UWSH, IMCA, alongside industry partners, launched a campaign to raise awareness of UWSH safety challenges. In January 2024, IMCA published IMCA D082 – Guidance on Diving Operations in Support of Underwater Ship Husbandry, providing practical, structured advice to vessel owners, operators, and contractors.

The guidance sets out a comprehensive framework covering the key factors that underpin safe operations, including:

• Competence and adequacy of diving personnel,
• Robust planning, risk assessments, and permit-to-work systems,
• Appropriate use of equipment and diving systems.

IMCA D082 is freely available to both members and non-members as part of IMCA’s commitment to improving safety standards across the diving industry. IMCA strongly advises all vessel owners and operators engaging UWSH services to ensure that work is carried out in full alignment with this guidance.

“Removing biofouling from vessels trapped within the Strait of Hormuz will be essential to maintain their operational efficiency and limit the transfer of invasive species between marine ecosystems,” added Bill Chilton. “However, too often, accidents occur when shortcuts are taken or risks are underestimated. Every operation must be planned and executed with safety as the overriding priority.”

As shipping activity in the region resumes, IMCA called on the industry to take a proactive approach to safety by ensuring it selects competent contractors, insists on appropriate equipment and procedures, and ensures that all diving operations are properly managed and supervised.

IMCA D082 – Guidance on Diving Operations in Support of Underwater Ship Husbandry is available to download here.