ten o'clock
Marking a large ocean tramp bound up-Channel , U75 dived deeply , so as to be free from any danger of being hit by her forefoot . With the noise of the tramp 's propeller to guide her , U75 followed , unsuspected , in her wake as she made for the Lizard Light . Arriving safely at the rendezvous , Kapitan Schwalbe waited until it was dark , and then cautiously brought the submarine awash . Punctually at ten o'clock a feeble violet light blinked through the night . It was U77 's call to her consort . `` What 's the game , I wonder ? '' asked Vernon , as a hail in German was borne faintly to their ears .