One of the (many) questions that I am asked about the Trent Severn Waterway is ‘why sections of the locks are painted blue’. Besides being pretty, the blue sections serve an important purpose, as they mark out the staging area for boats that are planning to go through the locks.
The section that is painted blue is called the Blue LIne. In the image above you can see the Blue Line there on the starboard (right) side of the downstream (lower) approach channel. The blue line is far enough back from the lock gates that the boats will not interfere with the safe operation of the lock, or the passage of boats exiting the lock.
Boats line up in order of arrival on the Blue Line to await the lockmaster’s instructions – an exception to this is when the lock gate is open and the boat is signalled by the lock master to directly enter the lock chamber. The Blue LIne is also used as an area where boats can tie up overnight if they missed the last lockage of the day – all boats in the area must leave before first lockage if they do not intend to pass through the lock.
And now you know…