<page_title> U-boat Campaign (World War I) </page_title> <section_title> Allied and Neutral Tonnage sunk by u-boats in World War I </section_title> <table> <cell> April <col_header> Month </col_header> </cell> <cell> 881,027 <col_header> 1917 </col_header> </cell> </table>
In April 1917, a record of 881,027 tons were sunk by the U-boats.