That is a very good question. I know that until the 1800's ships were christened by men, usually a high ranking officer or politician, or head of state. Then in the mid 1800's it gradually changed to women, especially with the reign of Queen Victoria.
Now as to why a woman is chosen to by the "Godmother" I am not sure.
__________________ Cruisemates Community Leader/Moderator
"There is a great difference between being well traveled and just having been to many places." ~Me