Operation Substance was a British naval operation in July 1941 during the Second World War to escort a convoy from Gibraltar

Gibraltar

Gibraltar is a British overseas territory located on the southern end of the Iberian Peninsula at the entrance of the Mediterranean. A peninsula with an area of , it has a northern border with Andalusia, Spain. The Rock of Gibraltar is the major landmark of the region...

 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...

.

The convoy was escorted by six destroyers and covered by aircraft carrier

Aircraft carrier

An aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...

 HMS Ark Royal

HMS Ark Royal (91)

HMS Ark Royal was an aircraft carrier of the Royal Navy that served during the Second World War.Designed in 1934 to fit the restrictions of the Washington Naval Treaty, Ark Royal was built by Cammell Laird and Company, Ltd. at Birkenhead, England, and completed in November 1938. Her design...

, the battlecruiser

Battlecruiser

Battlecruisers were large capital ships built in the first half of the 20th century. They were developed in the first decade of the century as the successor to the armoured cruiser, but their evolution was more closely linked to that of the dreadnought battleship...

 HMS Renown

HMS Renown (1916)

HMS Renown was the lead ship of her class of battlecruisers of the Royal Navy built during the First World War. She was originally laid down as an improved version of the s. Her construction was suspended on the outbreak of war on the grounds she would not be ready in a timely manner...

 and the battleship

Battleship

A battleship is a large armored warship with a main battery consisting of heavy caliber guns. Battleships were larger, better armed and armored than cruisers and destroyers. As the largest armed ships in a fleet, battleships were used to attain command of the sea and represented the apex of a...

 HMS Nelson

HMS Nelson (1925)

HMS Nelson was one of two Nelson-class battleships built for the Royal Navy between the two World Wars. She was named in honour of Horatio Nelson, 1st Viscount Nelson the victor at the Battle of Trafalgar...

 along with cruiser

Cruiser

A cruiser is a type of warship. The term has been in use for several hundreds of years, and has had different meanings throughout this period...

s and destroyer

Destroyer

In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...

s. On 23 July, south of Sardinia

Sardinia

Sardinia is the second-largest island in the Mediterranean Sea . It is an autonomous region of Italy, and the nearest land masses are the French island of Corsica, the Italian Peninsula, Sicily, Tunisia and the Spanish Balearic Islands.The name Sardinia is from the pre-Roman noun *sard[],...

, there were sustained Italian air attacks which resulted in one cruiser damaged and one destroyer sunk. The 11,000 tn troop transport Sydney Star was torpedoed by an Italian MAS

MAS (boat)

Motoscafo Armato Silurante , commonly abbreviated as MAS was a class of fast torpedo armed vessel used by the Regia Marina during World War I and World War II...

 boat and crippled, but the destroyer HMAS Nestor assisted her safe arrival to harbour. Eventually, all the merchant ships reached Malta and an Italian raid to sink them in Grand Harbour

Grand Harbour

Grand Harbour is a natural harbour on the island of Malta. It has been used as a harbour since at least Phoenician times...

 failed. Fairey Fulmar

Fairey Fulmar

The Fairey Fulmar was a British carrier-borne fighter aircraft that served with the Fleet Air Arm during the Second World War. A total of 600 were built by Fairey Aviation at its Stockport factory between January 1940 and December 1942...

fighters of the RN Fleet Air Arm and RN AA gunners shot down at least 12 Axis aircraft, while six Fulmars were lost.