IMCA Warns of High Risks in Underwater Ship Maintenance as Strait of Hormuz Activity Resumes

The International Marine Contractors Association (IMCA) has issued a stark warning regarding the significant dangers linked to underwater ship husbandry (UWSH) as vessel operations surge following the reopening of the Strait of Hormuz.

After a period of inactivity caused by regional conflict, approximately 600 vessels remain anchored in the Persian Gulf. The reopening has triggered a sharp increase in demand for hull cleaning, inspection, and maintenance services, essential to restoring vessel efficiency and protecting marine environments.

Bloomberg reports that orders for cleaning crews to remove algae, slime, and crustaceans from ship hulls have risen more than 30-fold since the announcement of an interim peace deal between the US and Iran. Prolonged idling has led to significant biofouling, which increases hydrodynamic drag, reduces fuel efficiency, and risks spreading invasive aquatic species across different marine ecosystems.

Despite its importance, IMCA emphasises that UWSH remains one of the most hazardous sectors within commercial diving. The association has been notified of multiple fatalities in recent years, often linked to unqualified or inexperienced dive teams and the use of inappropriate equipment such as self-contained underwater breathing apparatus (SCUBA) instead of safer surface-supplied systems.

Bill Chilton, Diving Manager at IMCA, stated: “Underwater ship husbandry continues to have one of the highest fatality rates in the diving industry. 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 address these risks, IMCA and its industry partners launched a safety awareness campaign. In January 2024, IMCA released IMCA D082 – Guidance on Diving Operations in Support of Underwater Ship Husbandry. This document offers practical and structured advice for vessel owners, operators, and contractors.

The guidance outlines a comprehensive framework focusing on key safety factors, including the competence and adequacy of diving personnel, robust planning with risk assessments and permit-to-work systems, and the appropriate use of equipment and diving systems.

IMCA D082 is available free of charge to both members and non-members, reflecting IMCA’s commitment to raising safety standards across the diving industry. The association strongly recommends that all vessel owners and operators engaging in UWSH activities adhere strictly to this guidance.

Chilton added: “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. 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 urges the industry to adopt a proactive safety stance by selecting competent contractors, insisting on appropriate equipment and procedures, and ensuring all diving operations are properly managed and supervised.

IMCA D082 – Guidance on Diving Operations in Support of Underwater Ship Husbandry can be downloaded from the IMCA website.