The Rupertinoe was an advanced naval gun designed by, and named after, Prince Rupert of the Rhine

Prince Rupert of the Rhine

Rupert, Count Palatine of the Rhine, Duke of Bavaria, 1st Duke of Cumberland, 1st Earl of Holderness , commonly called Prince Rupert of the Rhine, KG, FRS was a noted soldier, admiral, scientist, sportsman, colonial governor and amateur artist during the 17th century...

 in the 17th century.

Details

Naval warfare in the Restoration

English Restoration

The Restoration of the English monarchy began in 1660 when the English, Scottish and Irish monarchies were all restored under Charles II after the Interregnum that followed the Wars of the Three Kingdoms...

 period placed an emphasis on naval fire power

Fire power

Firepower is the military capability to direct force at an enemy. It is not to be confused with the concept of rate of fire, which describes cycling of the firing mechanism in a weapon system. It involves the whole range of potential weapons...

; as one writer has put it, warships had evolved into "floating artillery emplacements". The Rupertinoe gun was a response to this challenge. Designed by Prince Rupert, an experienced naval commander and senior admiral 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...

, the gun was intended for use against the Dutch

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

 during the Anglo-Dutch Wars

Anglo-Dutch Wars

The Anglo–Dutch Wars were a series of wars fought between the English and the Dutch in the 17th and 18th centuries for control over the seas and trade routes. The first war took place during the English Interregnum, and was fought between the Commonwealth of England and the Dutch Republic...

.

The Rupertinoe was a high specification, annealed

Annealing (metallurgy)

Annealing, in metallurgy and materials science, is a heat treatment wherein a material is altered, causing changes in its properties such as strength and hardness. It is a process that produces conditions by heating to above the recrystallization temperature, maintaining a suitable temperature, and...

 and lathe

Lathe

A lathe is a machine tool which rotates the workpiece on its axis to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation.Lathes are used in woodturning,...

 produced gun made at Rupert's foundry

Foundry

A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal in a mold, and removing the mold material or casting after the metal has solidified as it cools. The most common metals processed are aluminum and cast iron...

 at Windsor Castle

Windsor Castle

Windsor Castle is a medieval castle and royal residence in Windsor in the English county of Berkshire, notable for its long association with the British royal family and its architecture. The original castle was built after the Norman invasion by William the Conqueror. Since the time of Henry I it...

 reflecting Rupert's scientific interests in metallurgy

Metallurgy

Metallurgy is a domain of materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their mixtures, which are called alloys. It is also the technology of metals: the way in which science is applied to their practical use...

—he was the third founding member of the Royal Society

Royal Society

The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...

. Unfortunately the high cost of the gun—three times the price of a regular weapon—meant that by the Third Anglo-Dutch War

Third Anglo-Dutch War

The Third Anglo–Dutch War or Third Dutch War was a military conflict between England and the Dutch Republic lasting from 1672 to 1674. It was part of the larger Franco-Dutch War...

 (1672-4) only three ships had been equipped with it: the Royal Charles

HMS Royal Charles (1673)

HMS Royal Charles was a 100-gun first-rate ship of the line of the Royal Navy, designed and built by Sir Anthony Deane at Portsmouth Dockyard, where she was launched and completed by his successor as Master Shipwright, Daniel Furzer, in March 1673...

, the Royal James

HMS Royal James (1671)

HMS Royal James was a 102-gun first rate ship of the line of the English Royal Navy, built by Sir Anthony Deane at Portsmouth Dockyard at a cost of £24,000, and launched on 31 March 1671....

and the Royal Oak

HMS Royal Oak (1674)

HMS Royal Oak was a 74-gun third rate ship of the line of the Royal Navy, built by Jonas Shish at Deptford and launched in 1674. She was one of only three Royal Navy ships to be equipped with the Rupertinoe naval gun...

. The cost of the gun led to a fraud

Fraud

In criminal law, a fraud is an intentional deception made for personal gain or to damage another individual; the related adjective is fraudulent. The specific legal definition varies by legal jurisdiction. Fraud is a crime, and also a civil law violation...

 investigation by the Naval Commissioner Samuel Pepys

Samuel Pepys

Samuel Pepys FRS, MP, JP, was an English naval administrator and Member of Parliament who is now most famous for the diary he kept for a decade while still a relatively young man...

, although no evidence to support the claim was discovered.