FYI the canal at Lancaster that you were stood on IS 3ft deep – I've seen drunken fools jump into it during summer to cool off and walk around in it, it's waist deep across it's whole width.
I hacked a hole in the middle with a screwdriver (about 2") and pushed a stick down, and it's about 5', just level with my shoulders :o) Perhaps it's shallower by the pub, or the revellers were as tall as you James ?