Despite the inferior gunpowder of French artillery and the high number of shots fired by the bomb vessels, the British sustained more casualties and withdrew.

On 12 July Bonaparte issued an order for the assemblage at Boulogne of nine divisions of gun-vessels and of the same number of battalions of troops, besides several detachments of artillery to serve the guns on board the flotilla.

Rear-Admiral Latouche Tréville was appointed the commander in chief and was given directions to exercise the troops in ship-working, in firing the guns, in boarding and in getting in and out of the vessels.

Nelson, who recently returned from the Baltic, received detailed instructions of the admiralty to be employed in the defence of the mouths of the Thames and Medway, and all parts of the coast of Sussex, Essex and Kent.

At 5 am the next day the division of bomb vessels was placed ahead of the rest of the squadron and the attack began, although Nelson was aware that a long-distance naval bombardment was unlikely to be decisive.

At about 11 h. 30 m. pm the four divisions, who had crossed the Channel tied together, put off from the Medusa in good order, but they lost touch with each other because of the darkness of the moonless night.

Shortly before the dawn of the following day, some of his leading boats attacked a French brig near Boulogne pier and tried to carry it away, but she was moored with chains that could not be cut.