Admiral Charles Cooper Penrose-Fitzgerald (30 April 1841 – 11 August 1921) was a senior officer in the Royal Navy.

They had a son John Uniacke Penrose Fitzgerald (27 July 1888 – 11 December 1940) who also joined the navy and was killed on active service in World War II.

He was educated at Dr. Burney's academy, Gosport, and joined the navy in 1854 on board HMS Victory at Portsmouth.

Hercules had been involved in the rescue of Agincourt when her previous commander had allowed her to run aground near Gibraltar.

After Asia he spent a period on half pay and while in Ireland had a bad hunting accident which required him to lie flat for most of a year while recovering.

He was a proponent of Rear Admiral George Tryon's ideas that a simplified system of flag signals was needed for battle conditions.

He continued his writing career by contributing a biography of Admiral Rooke for From Howard to Nelson: Twelve sailors (1899) edited by John Laughton for Greenwich College.

In 1914 Penrose-Fitzgerald organised a group of thirty women in Folkestone to distribute white feathers to men not in uniform.

Being the log of Captain John Sirius" appeared in the July 1914 issue of The Strand Magazine.

The underwater menace came from the fictional country of Norland but was a thinly veiled reference to Germany's naval power.