 Later that month Hood 's armour scheme was slightly revised in light of further analysis of the results of Jutland and the deck armour was modestly increased in order to ensure that a minimum thickness of nine inches of armour would have to be penetrated by shells striking at angles of descent up to 30 ° from the horizontal . Further alterations were made in 1917 during her construction that increased the thickness of her turret faces and roofs . These changes , plus numerous others , increased her displacement by 600 long tons ( 610 t ) , her draught by 3 inches ( 76 @.@ 2 mm ) and reduced her speed to 31 knots ( 57 km / h ; 36 mph ) . The changes continued during 1918 when the thickness of her magazine crowns was increased from one inch to two ; the armour for the funnel uptakes above the forecastle deck was omitted in compensation . In May 1919 her main deck armour at the side abreast the magazines was increased to three inches ( 76 mm ) , and four 5 @.@ 5 @-@ inch guns and their ammunition were deleted in consequence . The next month plans were approved to increase the thickness of the main deck over the forward magazines to 5 inches ( 127 mm ) and to 6 inches ( 152 mm ) over the rear magazines ; her four above water torpedo tubes and their protection were to be omitted and the wall of the torpedo control tower were to be reduced to a thickness of 1 @.@ 5 inches ( 38 @.@ 1 mm ) to offset the armour 's weight . However , the additional deck armour was never fitted and the torpedo tubes ( less their protection ) were retained . 
