 The ship was used as a target to test the effect of various weapons on capital ships , along with Emperor of India . The tests included firing destroyer armament at the upper works at close range to test their effectiveness in a simulated night engagement , direct hits from 13 @.@ 5 @-@ inch shells , bomb tests , and experiments with flash tightness in the magazines . The first two tests were conducted in July 1931 , and were simulations of magazine explosions . The venting system worked as designed , and while the explosions caused serious internal damage , Marlborough was not destroyed , as the three battlecruisers had been at Jutland . In 1932 , further tests were conducted with dummy 250 @-@ pound ( 110 kg ) and 500 @-@ pound ( 230 kg ) bombs to test deck strength ; 450 @-@ pound ( 200 kg ) armour @-@ piercing ( AP ) bombs and 1 @,@ 080 @-@ pound ( 490 kg ) high explosive ( HE ) bombs were then detonated inside the ship to test their effectiveness . The Royal Navy determined that the HE bombs were useless , but that thick deck armour would be required to defeat AP bombs . This led to the decision to reinforce the deck armour of existing battleships throughout the 1930s . 
 The ship was used as a target to test the effect of various weapons on capital ships , along with Emperor of India . The tests included firing destroyer armament at the upper works at close range to test their effectiveness in a simulated night engagement , direct hits from 13 @.@ 5 @-@ inch shells , bomb tests , and experiments with flash tightness in the magazines . The first two tests <a href='uninflect' title='1'><mark>were</mark></a> conducted in July 1931 , and <a href='uninflect' title='2'><mark>were</mark></a> simulations of magazine explosions . The venting system worked as designed , and while the explosions caused serious internal damage , Marlborough was not destroyed , as the three battlecruisers had been at Jutland . In 1932 , further tests <a href='uninflect' title='3'><mark>were</mark></a> conducted with dummy 250 @-@ pound ( 110 kg ) and 500 @-@ pound ( 230 kg ) bombs to test deck strength ; 450 @-@ pound ( 200 kg ) armour @-@ piercing ( AP ) bombs and 1 @,@ 080 @-@ pound ( 490 kg ) high explosive ( HE ) bombs <a href='uninflect' title='4'><mark>were</mark></a> then detonated inside the ship to test their effectiveness . The Royal Navy determined that the HE bombs <a href='uninflect' title='5'><mark>were</mark></a> useless , but that thick deck armour would be required to defeat AP bombs . This led to the decision to reinforce the deck armour of existing battleships throughout the 1930s . 
Da ship was used as a target to test tdaeffect of various weapons on capital ships , along with Emperor of India . The tests included firing destroyer armament at the upper works at close range to test their effectiveness in a simulated night engagement , direct hits from 13 @.@ 5 @-@ inch shells , bomb tests , and experiments with flash tightness in thdaagazines . The first two tests was conducted in July 1931 , and was simulations of magazine explosions . Thedanting system worked as designed , and while the explosions caused serious internal damage , Marlborough was not destroyed , as the three battlecruisers had been at Jutland . In 1932 , further tests was conducted with dummy 250 @-@ pound ( 110 kg ) and 500 @-@ pound ( 230 kg ) bombs to test deck strength ; 450 @-@ pound ( 200 kg ) armour @-@ piercing ( AP ) bombs and 1 @,@ 080 @-@ pound ( 490 kg ) high explosive ( HE ) bombs was then detonated inside the ship to test their effectiveness . The daal Navy determined dat the HE bombs was useless , but that thick deck armour would be required to defeat AP bombs . dis led to the decision to reinforce the deck armour of existing battleships throughout the 1930s .