 Complete the following phrase:  On 15 March, the two battleships, with the two tankers in company, encountered a dispersed convoy in the mid-Atlantic. Scharnhorst sank two ships. Several days later, the main body of the convoy was located, and Scharnhorst sank another seven ships totaling 27,277 tons. One of the surviving ships radioed the location of the German battleships, which summoned the powerful British battleships Rodney and . Scharnhorst and Gneisenau used their high speed to escape in a squall, and the intervention by the British battleships convinced Lütjens that the chances of further success were small. He therefore decided to head for Brest in occupied France, which the ships reached on 22 March. Throughout the operation, Scharnhorst had difficulties with the superheater tubes in her boilers. Repair work lasted until July, which caused the ship to be unavailable during 