Pilots in Brazil have refused to board some ships with faulty air-conditioning, leading to voyage delays while new units are fitted, said Norwegian insurer Gard.
Temperatures of 30C to 35C in some northern ports have prompted concerns about working conditions for seafarers in pilot cabins and on the bridge.
In one case cited by the insurer, Amazon River pilots recorded a temperature of 28C on the bridge of one vessel leaving the port of Manaus and directed the vessel to anchor 675 km away at Santarem to repair a broken unit.
