HMS Thorn (N11) was a T-class

British T class submarine

The Royal Navy's T class of diesel-electric submarines was designed in the 1930s to replace the O, P and R classes. Fifty-three members of the class were built just before and during the Second World War, where they played a major role in the Royal Navy's submarine operations...

 submarine

Submarine

A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

 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...

. She was laid down by Cammell Laird

Cammell Laird

Cammell Laird, one of the most famous names in British shipbuilding during the nineteenth and twentieth centuries, came about following the merger of Laird, Son & Co. of Birkenhead and Johnson Cammell & Co. of Sheffield at the turn of the twentieth century.- Founding of the business :The Company...

 & Co Limited, Birkenhead

Birkenhead

Birkenhead is a town within the Metropolitan Borough of Wirral in Merseyside, England. It is on the Wirral Peninsula, along the west bank of the River Mersey, opposite the city of Liverpool...

 and launched in March 1941.

Career

Thorn had a short-lived career, serving in the Mediterranean.

Commencing operations in late 1941, Thorn sank the German tanker Campina, the Italian tanker Ninuccia, the Italian submarine Medusa, the Italian auxiliary patrol vessel AS 91 / Ottavia and the Italian transport ship Monviso. She also attacked an Italian convoy in the central Mediterranean, but failed to hit any ships.

On 7 August 1942 Thorn encountered the Italian torpedo boat Pegaso

Orsa class torpedo boat

The Orsa class were a group of large torpedo boats or destroyer escorts built for the Italian Navy in the late 1930s. They were an enlarged version of the , with more endurance and a greater depth charge load but less powerful machinery and a lighter gun armament. The surviving pair were rebuilt as...

, escorting the steamer Istria from Benghazi

Benghazi

Benghazi is the second largest city in Libya, the main city of the Cyrenaica region , and the former provisional capital of the National Transitional Council. The wider metropolitan area is also a district of Libya...

, off southern Crete. Pegaso spotted an escorting aircraft machine-gunning the sea’s surface and moved in to investigate. Just four minutes after the aircraft’s attack the Pegaso picked up a contact and carried out seven attacks after which contact was lost. Thorn failed to return from the patrol and is believed to have been lost in this attack. She was declared overdue on 11 August 1942.