Sperrbrecher
... that British spies helped sink some German minesweepers of the Sperrbrecher type, through determining how to adjust the fuses on magnetic mines?
... that British <a href="./Espionage" id="mwGKk" rel="mw:WikiLink" title="Espionage">spies</a> helped sink some <a href="./Nazi_Germany" id="mwGKo" rel="mw:WikiLink" title="Nazi Germany">German</a> minesweepers of the <i id="mwGKs"><b id="mwGKw"><a href="./Sperrbrecher" id="mwGK0" rel="mw:WikiLink" title="Sperrbrecher">Sperrbrecher</a></b></i> type, through determining how to adjust the fuses on <a class="mw-redirect" href="./Magnetic_mine" id="mwGK4" rel="mw:WikiLink" title="Magnetic mine">magnetic mines</a>?