Despite this, numerous aircraft continued to be operated during the Second World War, largely being confined to secondary roles away from the front lines, such as training and target tug duties.

Structural elements included stainless steel tubular spars and light alloy ribs; similar materials were used for the entire tail section save for the Alclad-plated fin.

[3] On 24 August 1933, Blackburn's B-6 prototype, powered by with a 700 hp (520 kW) Armstrong Siddeley Tiger IV engine, made its maiden flight at Brough.

[4] Following the completion of manufacturer trials, during which the engine was enclosed in a long-chord cowling, this prototype was delivered to the Aeroplane and Armament Experimental Establishment (A&AEE) at RAF Martlesham Heath for an official performance evaluation on 26 November 1933.

[6] During the following year, after the conclusion of testing at Martlesham, it was transferred to Gosport ahead of deck landing trials on board the aircraft carrier HMS Courageous.

During October 1934, the name Shark I was officially sanctioned; around this time, a series of modifications were implemented, the most visible of which was a lengthened engine cowling that enclosed the exhaust collector ring.

In this configuration, early test flights were conducted at Brough during April 1935; a successful series of sea trials took place at the Marine Aircraft Experimental Establishment Felixstowe.

[7][1] The Shark III differed from prior models in several respects, the most apparent of which was the addition of a glazed cockpit canopy and three-bladed Rotol wooden propellers.

Late on in production, assembly from components produced elsewhere took place at Blackburn's new factory in Dumbarton, Scotland, after which the completed airframes were transported by road to the Clyde at Abbotsinch (now Glasgow Airport) for flight testing.

[10] Frontline operations involving the Shark were curtailed after only a relatively short timespan, as the type had started to be replaced by the more capable Fairey Swordfish as early as 1937.

[13] During the Dunkirk evacuation conducted between 26 May and 4 June 1940, numerous Sharks flew across the English Channel to spot and illuminate Kriegsmarine E-boats using flares, they were otherwise unarmed; these operations were hindered and eventually stopped by poor weather conditions.

[16][15] On 10 April 1935, Blackburn successfully secured a contract over rival firms from the United States, Germany, Czechoslovakia, and Italy valued at £50,000 from the Portuguese government for six seaplanes.

[17] On 22 October 193, a long distance non-stop flight was conducted by a Portuguese Shark between Bom Succeso and RAF Calshot, carrying a diplomatic dispatch to London and returning six days later.

[18] During 1936, the Royal Canadian Air Force (RCAF) purchased seven Blackburn Shark II (760 hp (570 kW) Tiger VI), the first four of which were shipped in September of that year.