CHICAGO (CBS)– It’s that time of year, Chicago’s cruise vessels are leaving the Chicago River and heading to their winter homes.

The tour bots are docked at the Pier 11 Marina on the South Side of Chicago until Spring.

Vessels like the the Chicago Architecture Foundation Center River Cruise aboard Chicago’s First Lady undergo a “dry dock” inspections. This process involves driving the boat all the way to Manitowoc, Wisconsin for an inspection.

“Once they arrive, they take a 500-ton travel lift to get her out of the water so they can check to make sure her U.S.-made steel is in good shape, the bottom is not damaged and the framing/propellers etc. are okay,” a Chicago’s First Lady Cruise spokesperson said.

The boats will return to the Chicago river at the end of February or the beginning of March.