With the failiure of the 50 caliber 12 inch gun used on the St. Vincent through the Colossus class due to bore erosion and inconsistent propellant burning, British efforts instead went into developing a gun of bigger bore, as opposed to longer caliber. This lead to the 13.5"/45 caliber gun. In an effort to keep the ship at a reasnoble size, she became the first British battleship to feature an all-centerline battery, and the first to have superfiring guns fore, and aft. A battery of ten guns was chosen, with a length of 177m. One ship was authorised under the 1909/1910 budget, alongside the St. Vincent class HMS Hercules and the battlecruiser HMS Lion, although a contingency plan for three more battleships and one more battlecruiser was planned, and put into reality through public outcry.
Four ships were built; HMS Orion, HMS Monarch, HMS Conqueror and HMS Thunderer, all commissioned in 1912, alongside HMS Lion and HMS Princess Royal.
Wartime careers were uneventful, with the exception for the Battle of Justland. All four were decommisioned and scrapped, as per Washington Naval Treay.
HMS Orion as commisioned in 1912:
![[ img ]](https://i.imgur.com/Pqr1tKH.png)