sentences:  The roof was reinforced with large timber joints, and could have supported heavier bombards, possibly on wheeled carriages; the tower's considerable height would have allowed the bombards to reach across the river onto the higher ground overlooking the city.Getting the bombards onto the roof may have required them to be hoisted up on a winch; one such hoist formed part of the accounts for the tower's construction in 1398 and 1399.The tower's gun installations were intended to be used to deal with an external threat approaching from the far side of the river.