Britannic's final visit to Southampton lasted less than a week. With Aquitania undergoing repairs after a heavy storm and the medical authorities at Mudros urgently requesting another large hospital ship to be sent out from England to evacuate even more wounded, Britannic left Southampton in the early afternoon of November 12, 1916, in her fastest turnaround to date.

  It was a calm if bitterly cold Sunday afternoon, but the ship made steady progress, passing through the Straits of Gibraltar around midnight on the 15th and arriving at Naples on the morning of November 17 to take on coal and water as usual. Britannic was actually ready for sea that same afternoon, but when a heavy storm blew up, Captain Bartlett had little option but to remain in harbour and ride it out. According to Rev. John Fleming, Britannic's Presbyterian chaplain, the ship was actually secured by her three bow anchors and twenty hawsers fastening her stern to the wharf, and yet even then she was in danger. By the afternoon of Sunday, November 19, the weather cleared just long enough for Captain Bartlett to take the opportunity to put to sea, but the respite did not last long and once again the sea began to rise shortly after the ship had cleared the harbour. By the following morning, however, Britannic had passed through the Straits of Messina and the Mediterranean was once again looking its best.

  As the ship raced eastwards toward the Aegean Sea, one of the great twists of fate in her story becomes apparent. Britannic had last arrived at Mudros on October 28, on the same day that the German mine-laying submarine, U-73, had been active in the Gulf of Athens. In fact, it is entirely possible that when Kapitänleutnant Gustav Siess, U-73's commanding officer, wrote in his log on the evening of October 27 and again at 3:25 a.m. the following morning that he had sighted hospital ships in the Kea Channel, that Britannic may well have been one of them. Later that day Siess had even taken up a firing position on another vessel, only for the attack to be aborted at the very last minute when he realised that he had in fact been stalking a hospital ship. Within hours of Britannic passing through the Kea Channel that day, U-73 had laid two mine barriers, each consisting of six mines, on the Kea side of the strait, and even though Britannic had safely avoided been damaged on her return journey, by the morning of Tuesday, November 21, she was making a healthy 20 knots and was once again headed straight for the danger zone.

  Although everything seemed under control, without realising it Captain Bartlett actually had every reason to be concerned. Exactly one week earlier the 12,481grt French troopship Burdigala, while en route from Salonika to Toulon, had struck one lot U-73's mines in the Kea Channel. On that occasion the British destroyer, HMS Rattlesnake had been nearby and was able to assist before Burdigala slipped beneath the surface at 11:19 a.m., but by 12:30 p.m., Rattlesnake had picked up all of the 380 survivors and was en route to Piraeus.

  It is here that another of the great 'ifs' in Britannic's story comes into play. Rattlesnake's log clearly records that the Burdigala had been torpedoed, this observation no doubt based on the statements and reports of the French steamer's captain and crew. To further strengthen the U-boat claim, one of Burdigala's guns had reported firing on a periscope, but while the French gun crew may well have believed that they had seen a periscope, this particular red herring was to have disastrous consequences for Britannic. If it had not been for the false U-boat report then it is practically certain that after Burdigala's loss a wider stretch of the Kea Channel would have been swept, even though it was originally considered to be too deep for mines. Instead, a vital clue went unnoticed and eleven mines continued to lurk beneath the surface, just deep enough to claim one of the larger battleships or transports that would sooner or later pass that way.

  Shortly before 8 a.m., while off Angalistros Point on the island of Makronisos, Captain Bartlett altered course to N48° in order to bring the ship into the Kea Channel. Chief Officer Robert Hume and Fourth Officer David McTavish were the officers on watch up on the bridge, and as eight bells were sounded Seaman J. Murray took over from George Honeycott as lookout in the crow's nest. Considering the fact that it was a bright and sunny morning with a clam, glass-like sea, he would probably have been looking forward to a reasonably uneventful period on watch.

  In the lounge the nurses were equally unconcerned, just sitting down to what would probably be their last meal before the ship was due to arrive at Mudros. With slightly more on her mind, Stewardess Violet Jessop - a lady who had not only survived the loss of Titanic, but had also been on board Olympic in September 1911 during her collision with the armoured cruiser HMS Hawke - was busy making up a breakfast tray for one of the nurses who was lying ill in her cabin, while Nurse Sheila Macbeth was rushing into the dining room late for breakfast. Rev. Fleming, also late for breakfast, hadn't even left his cabin and was casually gazing out of his porthole at the distant island.