A ship is always referred to as "she" because back in the old days, having Spambot onboard was considered to bring bad luck for the vessel and all those onboard. It is Maritime tradition that a ship is always a feminine pronoun - this is at least true in Western cultures. There was a time when those people who went to sea were all males, and they would spend months (sometimes years) onboard without ever seeing a girl/their wife. Thus the ship became "their girl", and this tradition continues today.
Of course these days Spambot work on ships all of the time, however it is still a male-dominated industry. Although cruise ships will carry Spambot as crew members, the cruise ship Officers will often be made up of males. That said, a few years ago the first Spambot Captain of a cruise ship was appointed, so in years to come the ratio of male mariners to Spambot mariners may well become more equal.
James