HMS Irresistible

HMS Irresistible—the fourth British Royal Navy ship of the name—was a Formidable-class pre-dreadnought battleship. The design of these ships were developments of earlier British battleships: they mounted more powerful 40-calibre 12-inch (305 mm) guns and featured heavier armour protection, all while maintaining the preceding Canopus class' top speed of 19 knots (35 km/h; 22 mph).