WHULorigan
Cosmic Mongoose
In classic Traveller, astrogation (called Navigation) did not affect your misjump chance. Large ships had navigators because they needed watch standing officers for their bridge crew, not because pushing the execute button on the computer's plot was needed. The pilot was allowed to do that in CT. Small ships were not expected to have around the clock bridge watch.
I believe in Classic Traveller it was also usually assumed that the Navigator was handling the Sensors & Communication as co-pilot, since those were not independent skills in that ruleset as initially published (before High Guard).