Why were sailors often more literate than soldiers?

Was the average sailor more literate or intelligent than the average soldier?

Sailors tended to be more literate because naval work selected for mechanical skills and required more reading, not because soldiers were inherently less intelligent.

Navies needed personnel who could operate and maintain increasingly mechanical ships, which favored recruits able to read technical instructions. Sailors also encountered more manuals and wider travel during their work. The difference is explained by job selection and training rather than underlying intelligence.