Grain Tower was built between 1847 and 1855 in the Medway Channel to help protect the approaches to Chatham Dockyard. The tower was armed with three guns, two 32-pdr and a single 56-pdr. In 1884 these were all upgraded to 68-pdr SB guns.
From 1892 the whole tower was used as a Submarine Mining Station with two observation cells on the roof and the test room in what had been the barracks.
In 1912 two 4.7-inch Q.F. gun were mounted on the tower to defend the Boom defences and minefield.
During World War a Twin 6-pdr QF gun was mounted on the tower with extensive additions been made including a control tower and barrack block.
TNA WO 192/49