The Thunder-roller is another of the Chaos Dwarf Engineers' ingenious constructions. The vessel is propelled by two steam boilers, and is capable of a considerable turn of speed. Protruding from the front of the vessel is a huge iron roller, mounted on huge steel arms and covered with long spikes. Although these spikes churn up the water as the Thunder-roller powers forward and help pull the ship along, their real purpose is to tear apart enemy vessels by ramming into them.[1a]