Fearless rejoined Marlborough around 04:00 and both ships briefly fired at the German zeppelin L11. Commodore Reginald Tyrwhitt's Harwich Force had been ordered to reinforce the Grand Fleet, particularly to relieve ships low on fuel; they departed at 03:50 but this was too late for them to reach the fleet by morning, so Jellicoe ordered Tyrwhitt to detach destroyers to escort Marlborough back to port.Campbell, pp. 310–311 On the way, Marlborough and Fearless encountered the British submarines and ; the two submarines prepared to attack the ships but fortunately recognised them before they launched torpedoes.Campbell, pp. 317–318 By 15:00, eight destroyers from the Harwich Force had joined Marlborough and another pump had been lowered into the flooded boiler room. At around 23:30, the pump was being moved to clean it when the roll of the ship threw the pump into the damaged bulkhead, knocking the shores loose. Water flooded into the ship and Marlboroughs captain ordered Fearless and the destroyers to prepare to come alongside, to rescue the crew if the flooding worsened at 00:47 on 2 June. A diver was sent into the boiler room at that time, and he was able to keep the pump clean, which slowly reduced the water level in the ship.Campbell, pp. 325–326
