Why did sailors carry lemons and limes on board ships in the 17th century?

Waterways are often used for what? In which direction did the pilgrims sail? Who invented navigation? Who boarded the British ship late one night? What is a bundle of rope hung over a ships side called? What king and queen did coronado sail for? What style is nautical? Which winds did the early explorers prefer in their travels? What is a Any land smaller than a continent surrounded by water? Where can one take a competent crew course? Which inventions greatly contributed to the expansion of sea exploration in the 1400s? What islands are owned by France? How fast does a cargo vessel travels from Taiwan to Korea? How long would it take to sail from Florida to Argentina? When did roy orbison tour hull in the 1970s? What were the explorers names during the Spanish and Portuguese exploration? Where is sese islands? How does RCI work as a timeshare? What were the names of the thee ships that sailed to Jamestown? How many islands make up cuba?

Why did sailors carry lemons and limes on board ships in the 17th century?