What did the Egyptians invent to help them power their boats south on the Nile against the current

Egyptian civilization developed along the Nile River in large part because the river’s annual flooding ensured reliable, rich soil for growing crops.
Repeated struggles for political control of Egypt showed the importance of the region's agricultural production and economic resources.
The Egyptians kept written records using a writing system known as hieroglyphics.
Egyptian rulers used the idea of divine kingship and constructed monumental architecture to demonstrate and maintain power.
Ancient Egyptians developed wide-reaching trade networks along the Nile, in the Red Sea, and in the Near East.