As delivered, these carriers required modifications to conform to Royal Naval standards. The "Attacker" class ships had their conversions carried out in drydocks in United Kingdom, but due to these ports being overwhelmed 19 of the 23 ships of the "Ameer" class were converted by Burrard Dry Dock at Vancouver, British Columbia, Canada. These included extending the flight deck, fitting redesigned flying controls and fighter direction layout, modifications to the hangar, accommodation and store rooms, extra safety measures, oiling at sea arrangements, gunnery and other internal communications, extra wireless and radio facilities, ship blackout arrangements and other items deemed necessary for British service.