Simplify the following text for a Grade 4 native English-speaking person.
Original: It only operated as a lighthouse until 1860 , when a Pile Light was built and anchored off Shelly Beach , after which it served as a time ball tower .
Simplified: It only operated as a lighthouse until 1860 , when a Pile Light was built and anchored off Shelly Beach . It was then used as a time ball tower .