The St. Vincent class battleships consisted of three ships of the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 laid down in 1908, and completed between May 1909 and April 1910. They were St. Vincent

HMS St. Vincent (1908)

HMS St. Vincent was the lead ship of the St. Vincent class battleships of the British Royal Navy.She was commissioned on 3 May 1910 as 2nd flagship of 1st Division Home Fleet at Portsmouth. She was commanded by Capt. Douglas R. L. Nicholson and was flagship of Rear-Admiral Richard H...

, Collingwood

HMS Collingwood (1908)

HMS Collingwood was a dreadnought battleship of the British Royal Navy. Her design was essentially similar to the design of the previous ships, the . The Admiralty perceived in the planned building of German dreadnoughts a potential threat to the naval security of Great Britain, and saw the need...

, and Vanguard

HMS Vanguard (1909)

The eighth HMS Vanguard of the British Royal Navy was a St Vincent-class battleship, an enhancement of the "" design built by Vickers at Barrow-in-Furness...

. Vanguard was destroyed in an ammunition explosion, probably due to bagged cordite

Cordite

Cordite is a family of smokeless propellants developed and produced in the United Kingdom from 1889 to replace gunpowder as a military propellant. Like gunpowder, cordite is classified as a low explosive because of its slow burning rates and consequently low brisance...

.

Visually, they were very difficult to distinguish from the Bellerophons

Bellerophon class battleship

The Bellerophon class was a class of three dreadnought battleships that were built in the United Kingdom prior to World War I, and served in the Royal Navy during the war. The Bellerophons were near carbon copies of the previous , with the exception of a second tripod mast...

. The major innovation in this class was the adoption of longer 50 calibre main armament, increased from the 45 calibre fitted to previous classes.
The selection of a gun five feet longer than before necessitated a hull ten feet longer between X and Y turrets to maintain clearance between the guns and the superstructure.