CHICAGO (CBS) — The Chicago Police marine unit rescued nine passengers from a 31-foot powerboat that was taking on water last night a half mile off Diversey Harbor on Lake Michigan.

Deputy District Chief Paul Foercseh told WBBM Newsradio all were wearing vests.

“The passengers were brought on to the police marine unit, and then they were taken to Belmont Harbor, where they were examined,” he said. “All the passengers were OK, and they were released.”

The boat reported a mechanical problem and the police marine unit attempted to tow the boat after passengers were rescued.

However, the boat took on too much water–the line was cut–and the boat sank.

LISTEN: WBBM Newsradio’s Bernie Tafoya Reports