Were ancient (i.e., Greek and Roman; if you know about any other civilization, answer away, though) ships christened the way we do?
Ancient Greek Triremes were named, and naming ideas were not all that dissimilar from modern ship naming: Goddesses, place names, objects, etc.. Names are part of the information contained in the Tabulae Curatorum Navalium in the Epigraphical Museum in Athens.
The earliest known reference to a ship bearing a name comes from records of boat building under the Egyptian Pharoah Sneferu in the 27th c. BC.
Here a recorded vessel of 100 cubits volume and made of Cedar Wood is named as 'praise of the two lands' - a reference to the unification of upper and lower Egypt.
They were! One of the most important documents in the field of Indo-Roman trade which i specialize in is the so-called "Muziris Papyrus". This document gives the name of a particular ship that traveled between Egypt and India as the Hermapollon.