She was designed by Sir Edward Reed to a specific formula determined by the Board of Admiralty, and her purpose was never made wholly clear.

The Controller, the Fourth Sea Lord, stated that she was to be used for "the defence of our own harbours and roadsteads, and for attacking those of the enemy".

In reality, her lack of freeboard would appear to have precluded any operations whatsoever except those in calm weather and smooth water.

Glatton's raised amidships breastwork granted improved height above the waves for both her gun turret and hatches when compared to the U.S. model and it should be further noted that the Royal Navy successfully deployed the twin-turret breastwork monitors HMS Devastation and HMS Thunderer at sea with the fleet.

According to Admiral George Alexander Ballard, who served on board as a junior officer, stops were fitted to prevent the firing of the main artillery much past the beam, but not until some years after the ship was launched.