Generally speaking, ship type determines more than captain type in regards to overall tanking. Cruisers are fantastic at tanking, Escorts have a really hard time, and sci can tank well if they want, or they can load up with utility spells.

That said, Engineering captains are better at tanking than non-engineering captains flying the same ship, no matter what type of ship. Tactical captains are better at doing damage than non-tactical captains flying the same ship, and sci...uh...gets subnucleonic beam.