Original: Smaller ocean vessels of 3,000 tons or 9,000 tons and 5.5 m draft can reach as far as Iquitos, Peru, 3600 k from the sea.
Simplified: Smaller ocean ships of 3,000 tons and 7.9 m (26 ft) draft can reach as far as Iquitos in Peru, 3,700 km (2,300 miles) from the sea.