According to witnesses, it appeared the boat slammed into the dock after pulling in to the dock area too quickly around 6 pm.
The boat had just ended an architecture tour at the time of the accident.
Thom Serafin, spokesperson for Wendella Boat Tours released this statement Monday evening:
"This evening Wendella Boat Tours vessel The Lila ran into their dock near the Michigan Avenue bridge on the Chicago River.
Wendella, a third generation family-owned business that has been working on the Chicago River since 1935, is very concerned with the guests who were on board and extends our well wishes.
Wendella is conducting a full investigation in conjunction with the United States Coast Guard, who has jurisdiction over the Chicago River, but preliminary information suggest engine failure as the probable cause of the incident."