Smaller ocean vessels of 3,000 tons or 9,000 tons and 5.5 metres ( 18 ft ) draft can reach as far as Iquitos , Peru , 3,600 kilometres ( 2,200 mi ) from the sea .
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 .