Well, Lausanne, here's the story:
We fed the cat because he was hungry. Then it was REALLY cold so I picked him up and put him in the bathroom.
I sat with him there and thought "this guy needs a name we can call him. He's black but "Blackey" is dumb. He needs a diminutive too because Tam was a diminutive." At this point I realized that the was Mr Tam reincarnated. Just like Mr Tam, Jack told us his name and we added the "Tar" part. (Actually, Tam made us play Rumpelstiltskin.)
So why "Tar?" Because sailors appear unbidden and unwanted but, really, they can be an awful lot of fun. Just like our wee man.