Question to all Americans: why do you refer to vehicles and ships as "she"?

[BrianSoddingBoru4]

I found several explanations for this, here's the one I think may be closest:  Ships are referred to in the feminine because they're protective, in the manner of a human mother or a well-disposed goddess.  Your mum keeps you safe from harm, from the elements, and so forth (one source went so far as to call sailing ships 'wooden wombs').  This is reflected in that many private sailors name their boats after important women in their lives.  Referring to other vehicles in the feminine is very likely a case of simple cultural inertia.

Boru