 His conduct on the Helgoland resulted in a promotion to lieutenant for Sanders , and he was also recommended for command of his own ship . In February 1917 , he was appointed captain of HMS Prize , a three @-@ masted topsail schooner that was sailing under the German flag when it was seized in 1914 and converted to a Q @-@ ship in early 1917 . At midnight on 30 April 1917 about 180 miles south of Ireland , in the Atlantic , the Prize was attacked by a U @-@ boat , the U @-@ 93 commanded by Edgar von Spiegel von und zu <unk> . It was genuinely badly damaged by shellfire from the U @-@ boat 's deck guns . Sanders , remaining under cover , moved about the vessel reassuring his men . 
