UN to evacuate 11,000 stranded seafarers from Gulf after Iran-U.S. ceasefire deal

Following a U.S.-Iran ceasefire deal, the UN's International Maritime Organization is launching a phased operation to evacuate over 11,000 seafarers stranded in the Strait of Hormuz. While shipping has resumed, with at least 172 transits since June 17, 2026, demining operations and severe biofouling on hundreds of anchored tankers present major delays. Clearing the accumulated marine growth from ship hulls requires specialized diving teams, costing upwards of five figures per vessel.

Strait of Hormuz reopening

• ▪United States Secretary of State Marco Rubio warned that international law prohibits any country from imposing tolls on the Strait of Hormuz
• ▪The closure of the Strait of Hormuz since late February 2026 drove global Brent crude oil prices above $100 a barrel and choked off energy shipments
• ▪At least 172 vessels have transited the reopened Strait of Hormuz since the ceasefire deal was signed on June 17, 2026
• ▪The United Nations' International Maritime Organization is evacuating more than 11,000 stranded seafarers from the Gulf following a United States-Iran ceasefire deal

Biofouling removal from tankers

• ▪An oil supertanker has approximately 150,000 square feet of hull surface area that requires cleaning to remove marine growth
• ▪Over several months of anchorage, barnacles, mussels, clams, and algae have accumulated on hundreds of oil tankers in the Persian Gulf
• ▪Biofouling, the accumulation of marine wildlife on ship hulls, must be cleared before stranded tankers can safely transit the Strait of Hormuz

Maritime fuel efficiency impacts

• ▪Severe marine growth on propellers can render them useless, while organisms inside intake valves can break a vessel's cooling systems
• ▪Biofouling on ship hulls disrupts fluid dynamics, making vessels significantly less fuel-efficient and more expensive to operate
• ▪Fuel costs constitute approximately 50% of a ship's total operating expenses

Bottom cleaning operations

• ▪Bottom cleaning teams have increased their fees due to high demand, charging upwards of five figures per ship
• ▪Crews of five to six divers require four to five hours using hand scrapers and power washers to clear biofoul from each vessel
• ▪Divers must avoid scraping a ship's paint and special coating during cleaning to prevent ecological violations and insurance non-compliance

Insurance compliance requirements

• ▪Marine insurers include bottom-treatment clauses to ensure covered ships operate efficiently and comply with ecological standards
• ▪Maritime regulations require vessels to clear biofouling before reaching port to prevent the spread of invasive species

Strait clearance logistics

• ▪The standard Traffic Separation Scheme routing lanes through the Strait of Hormuz are currently unsafe due to the risk of floating mines
• ▪The International Maritime Organization's evacuation plan utilizes two temporary routes north and south of the standard Traffic Separation Scheme
• ▪The Oman Navy and the International Maritime Organization are coordinating a gradual, phased evacuation, contacting individual vessels with allocated transit days