On 21 September, "Yavuz Sultan Selim" was again sent out of the Bosphorus to drive off three Russian destroyers which had been attacking Turkish coal ships. Escort missions continued until 14 November, when the submarine nearly hit "Yavuz" with two torpedoes just outside the Bosphorus. Admiral Souchon decided the risk to the battlecruiser was too great, and suspended the convoy system. In its stead, only those ships fast enough to make the journey from Zonguldak to Constantinople in a single night were permitted; outside the Bosphorus they would be met by torpedo boats to defend them against the lurking submarines. By the end of the summer, the completion of two new Russian dreadnought battleships, and , further curtailed "Yavuz"s activities.