How big can a tanker get? There are bigger ones than this, but they haven't been in Halifax. Granted it isn't easy to get a sense of scale from the photo, until you zero in on the gangway amidships or the bridge.
The monster size Altair Trader arrived in ballast today for voyage repairs, and anchored in the lower harbour. The ship measures 160,216 gross tons and a staggering 311,110 deadweight tonnes. (The largest tankers that bring crude oil to Halifax might go half that size.) It was built in 2005 by Mitsui Engineering & Shipbuilding, Chiba Works in Ichihara (which is on the eastern side of Tokyo Bay.).
Due to its extreme size it took tug escorts inbound and outbound.
I wasn't able to track its entire progress arriving here, but it seems that it came from the Indian Ocean, via Capetown and across the Atlantic. I assume it unloaded somewhere (maybe Saint John) and is now headed for the next load.