 He also thought that they could be used on the decks of monitors and as such a dual purpose carriage was designed for the guns, which could be used both afloat and ashore.Only a limited amount of traverse was required for either role, but elevation had to be increased to 45° to maximize range.The concept was approved 23 September 1917, and Elswick was ordered to design the new 'B CD' mounts for delivery in five months.