 HMS Marlborough was an Iron Duke @-@ class battleship of the British Royal Navy , named in honour of John Churchill , 1st Duke of Marlborough . She was built at Devonport Royal Dockyard between January 1912 and June 1914 , entering service just before the outbreak of the First World War . She was armed with a main battery of ten 13 @.@ 5 @-@ inch ( 340 mm ) guns and was capable of a top speed of 21 @.@ 25 knots ( 39 @.@ 36 km / h ; 24 @.@ 45 mph ) . 
