Are you talking about one of these models?
http://www.freightlinertrucks.com/trucks/find-by-model/

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Or did you mean a Freighter,


or a (Cruise) Liner?



Just want to be clear...

The Lackawanna would be a decent tug to start out with.
Check out Harbor Models, or Loyalhannah Dockyard, or RCscalemodel for other options.