I wouldn't dream of disagreeing with the master, but would "JAPHETS" not be a better (albeit still not perfect!) fit?
Thus - "Ship-builder's son's" = "JAPHET'S"; old-style jests = "JAPES"; "capturing hearts" = "H".
I agree that this doesn't account for the "T", but neither does "JAPHETH", as far as I can see.
But, I await correction and enlightenment!