The rank of general at sea (occasionally referred to as "general of the fleet"), was the highest position of command in the English Parliamentary Navy (later the Navy of the Commonwealth of England, Scotland and Ireland), and approximates to the current rank of admiral. Alongside others, the generals at sea were also appointed as Commissioners for the Admiralty and Navy.
The generals at sea were referred to both by the title of 'general' and by their former army ranks interchangeably. Today, the title 'admiral' is also commonly – if incorrectly – used.
In February 1649, within a month of the execution of Charles I, the Council of State decided to put the office of Lord High Admiral into commission, and Colonel Robert Blake, Colonel Edward Popham and Colonel Richard Deane were appointed by Parliament as the first generals at sea and Commissioners for the Admiralty and Navy.
After Popham's death in 1651 he was succeeded in 1652 by General George Monck.
Deane was recalled to serve in the army in May 1651, before resuming his post as general at sea in 1652, but was killed at the start of the Battle of the Gabbard on 1 June 1653.
Following the death of Deane, Blake and Monck continued to serve alone until 3 December 1653, when Parliament decided to increase the number of generals at sea to four, with a quorum of two, appointing Major-General John Desborow and Vice-Admiral William Penn (who had been recommended by Monck) to serve alongside Blake and Monck as generals at sea, with all four also serving as Commissioners for the Admiralty and Navy along with Colonel Philip Jones, Colonel John Clerk, John Stone, Major William Burton, Vincent Gooking and Lieutenant-Colonel Kelsey.