Merrimack

The Merrimack was a Leviathan-class battlecruiser that had been converted into a prison ship. Stripped of everything useful apart from life support ("and even that was quirky at times"), it maintained geostationary orbit around Mar Sara's northern pole. Commanded by Captain Elias Tudbury, it was overtaken by the

Sons of Korhal
in order to free Raynor and his men.