When I first encountered this story, like everyone else I was spontaneously LOL - almost ROFL. And then, being the pathetic obsessive that I am, I fell to wondering just why it was so funny.
Saga Briggs describes humour as an “incongruity that is recognised and resolved in some way.” Other writers emphasise a situation vaguely established as threatening, but then reframed as benign. We're all familiar with black or gallows humour.
"Boat Boatface" would not really have been that amusing as the proposed name of a polar research vessel. Adding the suffix -y - Boaty - lends an air of indulgent affection, as if to a child. The ship has been contextualised as cuddly.
"Boatface" is an insult, the direct opposite of the cuddlyness of "Boaty" - but the real genius (for those immersed in English culture) is the "Mc" prefix, which makes the persona of the boat Scottish .. and therefore glum and dour.
The cognitive dissonance is complete: a soppy, cuddly prefix for the boat's first name, immediately followed by an insult suggesting the diametric opposite.
The overall effect is to ridicule and wrong foot the efforts of the vessel's pompous owner, presumably looking for "Endeavour" or "Polar Explorer" or something equally
We feel vaguely threatened by being invited to jump through hoops by authority. "Boaty McBoatface" subverts that pretty comprehensively: at the expense of a shocking racist stereotype of the Scotsman, who as we all know ... .
No to racist boat names, I say.