The Sea Hurricane Mk. IB was a standard Hawker Hurricane modified for carrier operations. These modifications included an A-frame type arrester hook, catapult spools and some strengthening to withstand carrier operations. Folding wings were considered, but the additional weight, design time required and delivery time delays that would be incurred resulted in them not being provided. As a result only the older carriers could operate Sea Hurricanes and store them below deck. Consequently when operated from HMS Illustrious, Formidable or Victorious they were let on deck, exposed to the weather.
A total of 340 were converted, with the first delivered in January 1941, and the first operational squadron 880NAS embarking on HMS Furious in July 1941.