HMS E11, commanded by Lieutenant Commander Martin E Nasmith, was one of the most successful submarines to take part in the Dardanelles campaign in 1915. During her 20 day patrol, E11's crew sank various Turkish vessels, including four transport ships, a gunboat, and several sailing boats carrying cargo.
E11 approached the Dardanelles region on 19th May. The crew's first mission involved capturing a Turkish dhow [sailing vessel] and tying it to the submarine's conning tower to act as a disguise. The plan was abandoned after several days as the disguise failed to attract any targets.
The submarine continued up the Sea of Marmara and finally had some success, sinking a gunboat and several other small craft on 23rd May. The following day, E11 encountered and sank the Turkish transport ship ‘Nagara', which was carrying supplies of ammunition. Nasmith then sank another transport and forced one aground, but had to turn about when the submarine came under attack from Turkish forces based onland.
E11 entered Constantinople [now Istanbul] harbour on 25th May. She was the first hostile vessel to enter the harbour in over 100 years. Nasmith sighted the large troop transport ‘Stamboul' and launched two torpedoes at the vessel. The second one struck its target, although the ship failed to sink. E11 then came under fire from shore-based artillery, but managed to escape.
The attack resulted in Turkey ceasing further attempts to reinforce troops at Gallipoli by sea. Apart from the practical value of disrupting Turkish supply lines, the attack had an enormous impact on Turkish morale and created a sense of panic in Constantinople.
The submarine then returned to the Bosphorus strait on 27th May, where it sank more ships.
E11's crew greatly respected Lieutenant Commander Nasmith's conduct during the patrol. For instance, Nasmith ordered the recovery of any torpedoes that missed their target. He was the first person to dive in to retrieve and disarm the first torpedo recovered.
E11 had been on patrol for nearly three weeks before she attempted to return to base in June. Nasmith feared that the passage through the Straits of Chanak would now be even more dangerous as the Turkish would be looking for them.
During the return passage through the Dardanelles, E11 encountered another transport. The submarine was running short of torpedoes and had mechanical by this stage. Despite these problems, Nasmith attacked and sank the ship with his final two torpedoes.
Later in the journey, Nasmith discovered that the submarine had snagged a mine on her forward hydroplane. He initially refrained from telling his crew and allowed the submarine to drag the attached mine. Nasmith only revealed the situation to his men nearly two hours later in order to give a series of swift orders designed to dislodge the mine. The mine and its cable luckily slipped clear of the bows and plunged away beneath them.
After a rest and refit in Malta, E11 returned to the Dardanelles in August and conducted two further patrols. Altogether, E11 crew succeeded in sinking over 80 vessels during her time in the Sea of Marmara.
Lieutenant Commander Nasmith also received the Victoria Cross for his role in E11's first patrol.