Her refit at Portsmouth Dockyard began in March 1914 and was interrupted by the declaration of war on Germany on 4 August. She'd been formally recommissioned the day prior, but the turret work required another week to complete. "Invincible" was the first battlecruiser to be fitted with a new fire-control director, but this could not be completed in the allotted time and would remain inoperable until she was refitted after the Battle of the Falkland Islands. She was declared operational on 12 August, when Rear-Admiral Sir Archibald Gordon Moore, commanding the 2nd Battlecruiser Squadron, hoisted his flag in her. He was ordered to the Humber, along with the battlecruiser , where he could better support the British ships patrolling the Broad Fourteens.