Liman is a little tart about the activities — or rather the lack of activity — of the German Navy. The story was spread in Germany, he says, that the Goeben and the German submarines carried the main burden of the defence at Gallipoli; but the Goeben never took part at all, and the U 21, having got safely through to Constantinople and been much fêted there, emerged only once again. She came out of the straits on July 4 and sank the French transport Carthage. Finding that his return route was blocked, Hersing turned west and steamed for the Adriatic, to be seen no more. Yet he had achieved his purpose. The mere threat of his presence off Gallipoli had scattered the Allied battle fleet, and his two sinkings were enough to keep it in harbour in the islands ever afterwards.
For the British submarines, however, the situation was rather more difficult; in order to make good the work that had already been done by Boyle and Nasmith they had to keep up the pressure in the Sea of Marmara and if possible increase it; and indeed, in all the records of the Royal Navy there is hardly anything that quite compares with the undersea offensive that now began. In a world that has since grown used to the unearthly courage of young men with fantastic machines it is still difficult to credit some of the things that happened. Six-pounder guns were fitted to the decks of the submarines to help them eke out their supply of torpedoes, and two new arrivals, the E 12 and the E 7, ran up to Constantinople, where they bombarded the powder mills, put a torpedo into the arsenal, cut the railway line and chased the trains along the shore. Soon the commanders learned to handle the changing density of the water, and they even turned it to advantage; by lying on top of the layer of heavier specific gravity when they wished to hide or rest they saved themselves the danger and difficulty of diving great depths to the ocean floor.
It was on Boyle’s third trip into the Marmara, on July 21, that a new hazard was discovered. As he passed through the Narrows he saw an obstruction under the water, and he reported this to Lieut.-Commander Cochrane in the E 7, when he met her in the Marmara next day. On July 24 Cochrane came out and he confirmed Boyle’s report: the Germans were building a net. He himself had been entangled in it for half an hour, ninety feet down.
This was a much more formidable obstacle than anything the submarines had encountered before. By the end of July it was completed — a vast steel mesh of two-and-a-half-inch wire stretching entirely across the straits, and reaching 220 feet down to the floor of the channel. A line of buoys painted alternately red and black supported it on the surface, and one end was secured on the peninsula about a mile north of Maidos, the other on a steamer anchored near Abydos on the Asiatic side. Turkish motorboats loaded with bombs patrolled the surface like spiders waiting at the edge of a web. Specially sited guns were set up on either bank.
There was a gate in the middle of the net, and unless the submarines were lucky enough to strike it their only way of getting through the wire was to ram it at full speed underwater and hope for the best. Boyle described this experience: ‘I missed the gate and hit the net. I was brought up from eighty feet to forty-five feet in three seconds, but luckily only thrown fifteen degrees off my course. There was a tremendous noise, scraping, banging, tearing and rumbling, and it sounded as if there were two distinct obstructions, as the noise nearly ceased and then came on again, and we were appreciably checked twice. It took about twenty seconds to get through.’
But Cochrane on his next trip did not get through. Hopelessly entangled, he fought the net for twelve hours on the bottom of the straits while bombs exploded about him, and it was only when the hull was leaking and the lights had failed that he burned his papers and rose to the surface to surrender.
Nasmith, Boyle and the others were not deterred; they continued to pass through, and by the end of the year the net was so damaged by their repeated rammings it had almost vanished altogether. Up to the last, however, the passage through the Narrows remained an ordeal of the most frightening kind, and perhaps from that very fact it acted as a psychological stimulus on the crews. One seems to have read the story in some boyhood book of sea adventure: the pirates’ cave with its treasure lies hidden in the cliffs, but one has to make a dangerous dive beneath the sea to reach it. And some get through and some get trapped halfway.
There is an almost dolphin-like air, a precise abandon, in the way the E-boats frisked about at times. On seeing a convoy, the commanders would deliberately surface and pretend to be in difficulties so as to entice the protective gunboats away. Then, diving deep, they would turn back and demolish the boats of the convoy one by one. They shot up the caravans of camels and bullock carts making their way down the Bulair isthmus with loads of barbed wire and ammunition. When they were short of fresh food they surfaced beside the Turkish trading caiques and provided themselves with fruit and vegetables. Wherever they could they saved their torpedoes and their ammunition by boarding enemy ships and simply opening the sea-cocks or placing a charge on the keel. Sometimes prisoners were carried around for days on end before they could be put ashore, and these were often very strange people — Arabs in their desert robes, sponge-divers and Turkish Imams, and once a German banker, wearing only a short pink vest, who complained that 5,000 marks in gold had just been sent to the bottom.
When more than one submarine was operating the commanders would make a rendezvous, and with their vessels tied up together far out in the Sea of Marmara they would exchange information for an hour or two, while their crews bathed in the sunshine; and then perhaps they would go off on a hunt together. Once there was a disaster. The French Turquoise ran aground and was captured. Enemy intelligence officers found in the captain’s notebook a reference to a meeting which he was to have at sea in a few days’ tine with the British E 20. It was a German U-boat that kept the rendezvous, and she torpedoed E 20 directly she came to the surface. Only the British commander and eight of the crew who were on deck survived.
In August Nasmith sank the battleship Barbarossa Harradin. Expecting that she would come south to take part in a new battle on the peninsula, he lay in wait for her at the top of the Narrows — having, on the way through, scraped heavily against a mine. The battleship appeared in the early dawn escorted by two destroyers, and she was taken utterly by surprise. She capsized and sank within a quarter of an hour.
Nasmith then went on to Constantinople and arrived just at the moment when a collier from the Black Sea had berthed herself beside the Haidar Pasha railway station. Coal at this time had become more precious than gold at Constantinople, since it was so scarce and since everything depended upon it — the railways and the ships, the factories, the city’s supply of light and water. A committee of officials was standing on the wharf discussing how the coal should be apportioned when E 11’s torpedo struck and the ship blew up before their eyes.
Next the submarine turned into the Gulf of Ismid, where the Constantinople-Baghdad railway ran over a viaduct close to the sea, and there d’Oyly-Hughes, the first officer, swam ashore and blew up the line. Like Freyberg at the beginning of the campaign, he was half dead when the E 11 picked him up again.