 Britain 's Naval Intelligence Division first proposed a commando raid on the dock in late 1941 . When the German battleship Tirpitz was declared operational in January 1942 , the Royal Navy ( RN ) and Royal Air Force ( RAF ) were already drawing up plans to attack her . Planners from Combined Operations Headquarters were looking at potential scenarios if Tirpitz escaped the naval blockade and reached the Atlantic . They decided the only port able to accommodate her was St Nazaire , especially if , like the Bismarck , she was damaged en route and needed repairs . They came to the conclusion that if the dock at St Nazaire were unavailable the Germans were unlikely to risk sending Tirpitz into the Atlantic . 
 Britain <a href='null_genetive' title='1'><mark>'s</mark></a>Naval Intelligence Division first proposed a commando raid on the dock in late 1941 . When the German battleship Tirpitz was declared operational in January 1942 , the Royal Navy ( RN ) and Royal Air Force ( RAF ) <a href='uninflect' title='2'><mark>were</mark></a> already drawing up plans to attack her . Planners from Combined Operations Headquarters <a href='uninflect' title='3'><mark>were</mark></a> looking at potential scenarios if Tirpitz escaped the naval blockade and reached the Atlantic . They decided the only port able to accommodate her was St Nazaire , especially if , like the Bismarck , she was damaged en route and needed repairs . They came to the conclusion that if the dock at St Nazaire <a href='uninflect' title='4'><mark>were</mark></a> unavailable the Germans <a href='uninflect' title='5'><mark>were</mark></a> unlikely to risk sending Tirpitz into the Atlantic . 
Britain  Naval Intelligence Division first proposed a commando raid on da dock in late 1941 . When tdaGerman battleship Tirpitz was declared operational in January 1942 , the Royal Navy ( RN ) and Royal Air Force ( RAF ) was already drawing up plans to attack her . Planners from Combined Operations Headquarters was lookin at potential scenarios if Tirpitz escaped the naval blockade and reached the Atlantic . They decided thdanly port able to accommodate her was St Nazaire , especially if , like the Bismarck , she was damaged en route and needed repairs . They came to thedanclusion dat if the dak at St Nazaire was unavailable the Germans was unlikely to risk sendin Tirpitz into the Adantic .