She passed through the net at 80 feet depth and carried a portion of it with her. This portion must have had some of the heavy weights attached that had been holding the net down, for as the boat came through she took a big angle down by the bow and sank.
The forward hydroplanes caught in the net jammed at "10° of dive." "E 12's" external tanks were blown out and full speed put on the motors. The boat continued down, however, and as the pressure increased, the conning-tower glass scuttles burst in and the conning-tower filled up, the hull leaked forward, and the fore compartment had to be closed off. By putting three men on the wheel the bow hydroplanes were moved a little, and after ten minutes at 245 feet the boat started to rise. They managed to check her at 12 feet, but found her almost uncontrollable. Six patrol boats opened fire as the conning-tower showed above water, and then the panting hydroplane men forced her down again. The boat continued to dive badly (she was still towing the net and sinkers), and twice she ran down to 120 feet. Both diving gauges had failed and the gyroscopic compass had followed suit. The conning-tower (magnetic) compass was flooded out and useless. Then at 80 feet she struck chain moorings off Kelid Bahr and scraped past. This broke away the length of net she had been towing, and released of the weight she rose at once, and before the tanks could be filled again broke surface. The shore batteries and patrol vessels opened fire at once, hitting the conning-tower full with a small shell and sending other small shells and splinters through the bridge. As the boat went down (the conning-tower being flooded already, the shell hole was nothing to worry about) a torpedo fired from Kelid Bahr passed over her, and another 50 yards astern of her. "E 12" continued her dive towards home, her trim and control being then normal. She observed two large explosions a couple of miles astern of her and saw the track of another torpedo, but was not further molested, and joined the Dardanelles Fleet a few hours later.
Submarine "H 1" (Lieutenant Pirie) has been mentioned as having worked in company with "E 12." An "H" boat is, of course, much smaller and less seaworthy than an "E," being of 400 tons and 150 feet length. Before meeting "E 12" at the rendezvous, this boat had sunk a steamer. Later she sank three more steamers and a dhow. As "E 12" was leaving the Marmora first, she politely took "H 1's" mails out with her.