The German plan was for '' Stier '' , disguised as the minesweeper '' Sperrbrecher 171 '' , to be escorted through the English Channel to Gironde , and from there to break out to the Atlantic to attack Allied merchant ships .
The German plan was for '' Stier '' , disguised as the minesweeper '' Sperrbrecher 171 '' , to be escorted through the English Channel to Gironde , France . 
 From there , '' Stier '' was to break out into the Atlantic to attack Allied merchant ships .