Is ship a common noun

Yes, the noun ship is a common noun, a general Word for any ship of any kind.

A proper noun is the name of a specific person, place, thing, or a title; for example:

• "Professor Katsman", a Russian cargo ship built 2008
• Ship Bottom, NJ 08008
• Royal Mail Ship (RMS) Titanic
• "Ship of Fools" 1965 movie with Vivien Leigh and Simone Signoret