It differed from the conventional tactics of naval assaults of the period by utilizing a wide range of new equipment produced by the American inventor Robert Fulton, with the backing of the Admiralty.

Preparations for an invasion flotilla to carry French troops across the Channel from a number of ports had been underway since the late 1790s, but had been temporarily shelved by the Peace of Amiens.

The resumption of hostilities resulted in the gathering of forces outside Boulogne, the construction of large military camps and the fortification of port in preparation for the assembling of the invasion flotilla.

Unless the French invasion fleet could be destroyed either in port or at sea, it was doubtful that the south of the country could be held in the immediate aftermath of a landing and advance on London.

[4] With tensions running high in Britain, prominent politicians suggested attacking the French force in port, in the hopes of at the very least delaying the anticipated invasion while defences were hurriedly constructed along the coast.

Prime Minister William Pitt the Younger met with a number of inventors and amateur tacticians during the year, who proposed new and novel ways of attacking the French before they could put to sea.

Ideas included sinking blockships in the harbour mouth, releasing rocket-carrying balloons over the port at night to be detonated by clockwork, or sending in a fleet of fireships.

[9] In the meantime the frigate HMS Immortalite was sent under the command of Captain Edward Owen to carry out surveys along the French coast around the port.

[16] The French began to construct a series of booms and chains across the entrance to frustrate similar attacks in the future, which took time and put them in a defensive rather than offensive mode of thinking.

[16] The nature of the devices used in the attack provoked derision from much of the British public, who regarded it as an unfair and unsporting method of waging war.

[18] Fulton made another attempt to use his devices against the fleet at Boulogne on 19 September 1805, this time in company with Sir Sidney Smith, but again the attack did not produce any significant results.