Meanwhile, Nasmith and his men were struggling for their lives. The current in the Bosphorus was even stronger than in the Dardanelles, and for some twenty minutes the submarine was out of control, bumping from shoal to shoal along the bottom as far as Leander’s Tower. She was righted eventually, and with great skill Nasmith turned back through Constantinople. ‘The next day,’ here-ported later, ‘was spent resting in the centre of the Sea of Marmara.’

Then on May 27 he resumed his attack, sinking ship after ship in the approaches to the Golden Horn. A terror spread through the Sea of Marmara, for it was thought that at least half a dozen submarines were operating. No vessel of any size was allowed to leave port without an escort of destroyers and gunboats, and these repeatedly tried to ram the E 11 whenever she rose to the surface to attack. Nasmith paused in his operations only when the air in the submarine became so foul that he was obliged to surface in order to allow the crew to come on deck and bathe.

Soon the shortage of torpedoes became the E 11’s chief concern, and those that remained were set to run on the surface so that whenever they missed their targets Nasmith could dive into the sea and recover them. By June 5 a serious defect had developed in the port main motor, the starboard intermediate shaft had cracked, only two torpedoes were left, and Nasmith judged it time to go home. He entered the Dardanelles and steamed down as far as Chanak hunting for the Turkish battleship Barbarossa Harradin, upon which he had made an unsuccessful attack a few days before. He saw nothing, however, except a large transport anchored above Nagara. The E 11 was now in the most dangerous part of the Narrows, and in her crippled state was quite likely to be washed ashore. But it was unbearable to Nasmith that he should leave with two torpedoes still intact; he turned back up the Dardanelles, sank the transport, and then returned for the crucial dive through the Narrows. Off Chanak the trim of the boat became violently affected by the change in the density of the water, and Nasmith dived to seventy feet. About an hour later he heard a scraping noise which seemed to indicate that the keel was hitting the bottom, and since he knew this to be impossible he rose up to twenty feet below the surface to investigate. He saw then that about twenty feet ahead of the periscope a large mine had been torn from its moorings by the port hydroplane and was being towed along. Saying nothing to his crew, Nasmith continued for another hour until he was outside the entrance to the straits. He then went full speed astern with the bows of the submarine submerged and the rush of water from the screws carried the mine away.

There was another dinner aboard the flagship that night, and at the end of it Boyle in E 14 set off again for the Marmara, while Lieut.-Commander Nasmith, V.C., sailed the E 11 to Malta for repairs.

An extreme crisis had overtaken the Allied Fleet while Nasmith had been away, and it was every bit as serious as the alarm which he had created in Constantinople. Towards the middle of May news had come through that a U-boat (it was Hersing in the U 21) had been sighted passing through the Straits of Gibraltar. It had been fired at but had got away, and was then presumably headed for Gallipoli.

During the next week, when Nasmith in the E 11 had vanished into the silence of the Sea of Marmara, there had been a growing depression in the Fleet. The Queen Elizabeth had been something of a symbol for the whole expedition, and it had seemed to the soldiers on shore as well as the sailors at sea that a good few of their hopes had gone with her when she sailed away. De Robeck had transferred his flag to the Lord Nelson, and had remained off the peninsula with the other battleships, but it was not the same thing. The Fleet had an apprehensive air. Each day the tension increased, and the men on watch kept seeing periscopes on every side. A gambolling porpoise was enough to raise the alarm, and so were the dead and bloated mules that floated out to sea from the battlefield on shore, their legs projecting to the sky.

In the very early dawn of May 24 a genuine emergency occurred: the old battleship Albion ran her bows on to a sandbank off Gaba Tepe and the Turks fired more than a hundred shells into her while the British tried to tow her off. Eventually the ship lightened herself by firing off all her heavy guns together, and in the recoil she got away. This incident had nothing to do with submarines, and there were under a dozen casualties, yet it was one more addition to the general feeling of insecurity.

Then on the following morning — at the very moment that Nasmith was gliding into the wharves at Constantinople — the Vengeance reported that a torpedo had passed across her bows while she was steaming between Anzac and Helles. It was true enough. Hersing had managed to get into the Austrian port of Cattaro before his oil ran out, and when he had refuelled he came straight through to Gallipoli.

A commotion spread through the Allied ships. De Robeck in haste transferred his flag again from the Lord Nelson to the Triad, a large yacht which had once been a pleasure-going ship along the Bosphorus, and all the more valuable battleships and transports were ordered to retire at once to Mudros. There was a feeling of desolation in the Army as the ships vanished over the horizon leaving behind them an unfamiliar, almost empty sea. Those few of the larger vessels that remained could not disguise the atmosphere of tension in which they waited, hour by hour, for the hidden attack which now seemed bound to come.

Commander Hersing struck at mid-day. He saw the old battleship Triumph near Gaba Tepe with a ring of destroyers circling round her, waited for his chance, and fired. The torpedo passed easily through the Triumph’s nets and the ship at once took a heavy list. For eight minutes, while the destroyers came rushing in to the rescue, she remained at an angle of forty-five degrees, spilling her crew into the sea. Then she capsized and floated for a time with her green bottom upwards in the sunlight. The crews on the neighbouring ships stood to attention as she made her last plunge down to the bottom through clouds of smoke and steam. All this took place in full view of the two opposing armies on the shore, and while the Anzac soldiers watched in dismay a cheer came up from the Turkish trenches. This was the finest sight the enemy had seen since the campaign began, but they had no wish to be vindictive; after a few opening shots no further attempt was made to fire on the wreck or her survivors.

The Triumph was a twelve-years-old ship of 11,800 tons, and only seventy-one men had gone down with her, but this was the end of the security of all battleships at Gallipoli. De Robeck gave orders for a further retirement, and presently the Majestic, the oldest battleship of them all, was left alone with a screen of destroyers off Cape Helles. Admiral Nicholson, the commander of the flotilla there, came aboard her from the Swiftsure during the course of the afternoon. So eager were Nicholson and his staff to let the Swiftsure get away that they did not wait to pack their belongings; baggage, bedding, tinned preserves and an assortment of wines were dumped in a trawler and ferried across in a matter of minutes.

Few believed that the Majestic would survive, and the soldiers in their dugouts kept watching her all afternoon as she cruised along the shore. By nightfall, however, nothing had happened, and the old battleship went back to Imbros in the darkness. Some fishing nets had been erected across the mouth of the open harbour there, and these she carried away on her first attempt to enter; but otherwise no harm came to her through the night. Keyes went out in the destroyer Grampus hoping to ram the enemy submarine if she surfaced, but he saw nothing.