Sable, a castle embattled argent, masoned sable, over which a third tower with three turrets of the same and upon this tower an escutcheon azure bearing a dove standing argent.
(Glossary of Heraldic Terms)
The identifying device is taken from the coat of arms of Montcalm, the courageous defender of Quebec against General Wolfe. In Montcalm's arms, the fourth quarter shows a white (argent) tower with three turrets against a black background, while the first quarter displays three white doves on a blue field. The Montcalm tower has been placed above the device common to all gate vessels. This is a stone wall with an entrance way and supported by two towers. On the Montcalm tower has been placed a blue shield bearing a white dove (from his arms) which, coupled with the protective stone wall, suggests that the gate vessel, like the wall, stands to maintain peace within by keeping the enemy out. All porte class vessels of the Royal Canadian Navy are named for gates of Canadian fortresses and walled cities or towns. Porte Quebec was one of the gates of the City of Montreal.
Porte-class gate vessel
Azure blue and white
Badges Of The Canadian Navy by Arbuckle, J. Graeme. Halifax: Nimbus Publishing, 1987.
CFP 267 - Badges of the Canadian Forces, Minister of Supply and Services Canada, 1977.