Character Analysis
This character is a one-trick pony. A retired navy admiral, he fires a cannon signaling the time of day from the top of his roof. This adds comic moments to the film as the Banks family scrambles to prevent vases and lamps from falling over in their house after the sound of the shot.
And, oh—Admiral Boom is a racist. Can't forget that part.
There's an example in Mary Poppins of the kind of racial humor it was hard to detect when you were a kid, but seems glaringly obvious as an adult (like the three black crows in Dumbo).
During the "Step in Time" number, Boom sees the chimney sweeps dancing around on a nearby rooftop. Misunderstanding what's happening he says:
ADMIRAL BOOM: We're being attacked by hottentots!
The term "hottentots"—which is derogatory—was actually used to refer to a group of people from South Africa. And, since the chimney sweeps are covered in soot, the "joke" is supposed that Boom mistakes them for being black.
Oof. Not so great, Disney.