While the COG slowly phased out their capital-class Battleships with those of Aircraft Carriers like the Raven's Nest Class, the UIR still maintained a fleet of these formidable surface vessels.
These ships were quite formidable, possessing three triple-barrelled naval big guns which could provide heavy artillery bombardment on coastal cities, towns and beaches.
Battle of Gatka Ridge
After the discovery of an Imulsion source upon the island of Knifespire, a UIR battleship under the control of the Gorasni was sent to the island escorted by a fleet of ten Gelen Class Frigates. A trio of COG Corvas armed with Hunter torpedoes attempted to sink the battleship, but the one torpedo that they managed to fire sank a frigate instead. Ghost Wyatt Callahan, who used his armor's rescue beacon to paint the target for the Corvas, managed to board the ship and reach the fuel tanks. Wounded in the process, Wyatt broadcast a final message to his brother Lieutenant Colonel Gabriel Diaz before blowing up the battleship's fuel tanks with a shaped charge. The explosion triggered the battleship's ammunition room, obliterating the battleship in a catastrophic explosion. The shockwave and shrapnel took out all of the UIR frigates which had gathered in close to protect their flagship when the Corvas had attacked.
Battle of Bonbourg
The fleet proceeded to bombard COG positions in Bonbourg when it was hit by the COG's Hammer of Dawn satellites, which sank four ships - one of which was a Battleship - and forced a hurried retreat for the Third Fleet.
The loss was humiliating and devastating for the UIR's navy as well as demoralizing in the upper echelons of UIR leadership. Two weeks later, the fleet's commander informed the rest of the fleets' captains that the UIR had capitulated, ending the Pendulum Wars.