HMS Parthian (N75) was the lead boat

Lead ship

The lead ship or class leader is the first of a series or class of ships all constructed according to the same general design. The term is applicable military ships and larger civilian craft.-Overview:...

 of the six 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...

 s, all launched in 1929. The submarine was sunk in 1943 during the Second World War. The submarine was nicknamed Peanut

Peanut

The peanut, or groundnut , is a species in the legume or "bean" family , so it is not a nut. The peanut was probably first cultivated in the valleys of Peru. It is an annual herbaceous plant growing tall...

, from the identity letters PN painted on the fin

Sail (submarine)

In naval parlance, the sail or fin of a submarine is the tower-like structure found on the dorsal surface of submarines...

.

Parthian spent most of her Second World War service in the Mediterranean. On the outbreak of the war, she was on the China Station

China Station

The China Station was a historical formation of the British Royal Navy. It was formally the units and establishments responsible to the Commander-in-Chief, China....

, but was transferred to Alexandria

Alexandria

Alexandria is the second-largest city of Egypt, with a population of 4.1 million, extending about along the coast of the Mediterranean Sea in the north central part of the country; it is also the largest city lying directly on the Mediterranean coast. It is Egypt's largest seaport, serving...

 in May 1940. She sank the Italian submarine Diamante near Tobruk

Tobruk

Tobruk or Tubruq is a city, seaport, and peninsula on Libya's eastern Mediterranean coast, near the border with Egypt. It is the capital of the Butnan District and has a population of 120,000 ....

 on 20 June 1940. By the end of the year she had been attached to the 8th Submarine Flotilla based at Malta

Malta

Malta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in...

.

She also sank the Vichy French

Vichy France

Vichy France, Vichy Regime, or Vichy Government, are common terms used to describe the government of France that collaborated with the Axis powers from July 1940 to August 1944. This government succeeded the Third Republic and preceded the Provisional Government of the French Republic...

 submarine Souffleur off Beirut on 25 June 1941, during the combined British/Free French campaign to occupy Syria

Syria

Syria , officially the Syrian Arab Republic , is a country in Western Asia, bordering Lebanon and the Mediterranean Sea to the West, Turkey to the north, Iraq to the east, Jordan to the south, and Israel to the southwest....

 and Lebanon

Lebanon

Lebanon , officially the Republic of LebanonRepublic of Lebanon is the most common term used by Lebanese government agencies. The term Lebanese Republic, a literal translation of the official Arabic and French names that is not used in today's world. Arabic is the most common language spoken among...

. Parthian underwent a refit in the USA from late 1941 until March 1942 before returning to the Mediterranean, where she carried out supply operations between July and October to Malta

Malta

Malta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in...

 carrying aviation fuel

Aviation fuel

Aviation fuel is a specialized type of petroleum-based fuel used to power aircraft. It is generally of a higher quality than fuels used in less critical applications, such as heating or road transport, and often contains additives to reduce the risk of icing or explosion due to high temperatures,...

 and ammunition

Ammunition

Ammunition is a generic term derived from the French language la munition which embraced all material used for war , but which in time came to refer specifically to gunpowder and artillery. The collective term for all types of ammunition is munitions...

. To increase her cargo capacity, one of the batteries was removed and no spare torpedoes were carried. In May 1943 the submarine sank a number of Italian sailing vessels in the Aegean Sea

Aegean Sea

The Aegean Sea[p] is an elongated embayment of the Mediterranean Sea located between the southern Balkan and Anatolian peninsulas, i.e., between the mainlands of Greece and Turkey. In the north, it is connected to the Marmara Sea and Black Sea by the Dardanelles and Bosporus...

.

The submarine left Malta on 22 July 1943 for a patrol in the southern Adriatic. She was diverted to a patrol area off Otranto

Otranto

Otranto is a town and comune in the province of Lecce , in a fertile region once famous for its breed of horses.It is located on the east coast of the Salento peninsula. The Strait of Otranto, to which the city gives its name, connects the Adriatic Sea with the Ionian Sea and Italy with Albania...

 on 26 July, and diverted again on 28 July. The submarine was signalled on 6 August to leave the patrol area but the signal was not acknowledged. Parthian failed to arrive at Beirut

Beirut

Beirut is the capital and largest city of Lebanon, with a population ranging from 1 million to more than 2 million . Located on a peninsula at the midpoint of Lebanon's Mediterranean coastline, it serves as the country's largest and main seaport, and also forms the Beirut Metropolitan...

, where she was due on 11 August. It is likely that she was sunk by a naval mine

Naval mine

A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...

 near Brindisi.

One crewmember lost with Parthian was Timothy Walker, the son of Captain Frederic John "Johnny" Walker

Frederic John Walker

Captain Frederic John Walker, CB, DSO and three Bars, RN was a British Royal Navy officer noted for his exploits during World War II...

, a leading U-boat hunter.