Original sentence: Once dismantled, the complex kit of almost 3,481 parts was transported by cargo ship to Portuguese East Africa, then towed by barge up the dangerous waters of the Zambezi.The other parts of the ship were man-handled or carried on the heads of men and women over difficult terrain and across river beds: they averaged only  a day
Edited sentence: Once dismantled, the gigantic kit of almost 3,500 parts had to be transported by cargo ship to Portuguese East Africa, then towed by barge up the dangerous waters of the Zambezi.The other parts of the ship were man-handled or carried on the heads of men and women; over difficult terrain and across river beds, they averaged only  a day