Air Draft Max height to travel the following path. 1.) Hudson into Lake Ontario (via Eire Canal) Bridge Clearance on the Erie Canal is 20 feet. There is normally one foot extra. 2.) Trent-Severn Waterway Bridge Clearance on the Trent-Severn Waterway is 22 feet. 3.) Rideau Canal then to the Saint Lawrence via Montreal Bridge Clearance on the Rideau Canal is 22 feet 4.) Saint Lawrence to Lake Champagne then to Hudson. Bridge clearance on the Champlain Canal is 17 feet. due to a R/R bridge at Whitehall. A R/R bridge at Mechanicville is 15.5 feet but can be increased with advance notice. Alan Lloyd Author, Great Loop Navigation Notes _www.NavigationNotes.com_ (http://www.NavigationNotes.com)