NYACK - The New York State Thruway Authority has ordered GPS units be installed on all construction barges and boats surrounding the Tappan Zee Bridge to ensure a safe boating season this year.

Three construction barges have come loose from their moorings since September, sending the boats floating down the Hudson River. The NYS Thruway Authority ordered a $1 million a month fine against Tappan Zee Constructors over the barge mishaps.

Brian Conybeare, Gov. Cuomo's special advisor on the new Tappan Zee Bridge, says safety is a priority when building the new bridge. So far, eight GPS units have been installed, with 150 more on the way. A "Geo Fence" will be created once all are installed and Conybeare says an alarm will go off if a boat breaks free and crosses it.

Tappan Zee Constructors did not return News 12's calls for comment on the pace of the GPS installations.