- Feb 2019
Napoleon had called off the 1805 invasion, yes, but he certainly did not abandon the idea of an invasion permanently. Even after the loss at Trafalgar he was intent on rebuilding the navy to make another attempt sometime in the future. Luckily for the British he was defeated before his navy could reach a significant size again.
Not true. From 1807 onwards he took up a large shipbuilding programme and by 1811 at Toulon his fleet outnumbered the British blockading squadron. By 1812-1813 he had 80 ships of the line with roughly 40 or so more under construction. His fleet reached a significant size and even after Trafalgar he still had 4 more minor fleets. The naval threat was always there to a degree and while Bonny didn't understand naval warfare and had inferior* ships to the British he did have a significant fleet in size. The British blockade prevented him from doing too much with it but he had the fleet, he also had many privateers and raiders to attack British merchant shipping.
I also have to agree with @pugsville on the idea that the French invasion was hardly possible regardless if Trafalgar happened or not or if Nelson commanded or not. The French simply didn't have the commanders, quality and the general means to land, let alone hold in Britain. The British blockade sealed their fate before Trafalgar even began. The French challenged Britain in the Atlantic, the Indian Ocean etc. but this would not let them achieve an invasion of Britain itself. Even if they managed to break the blockade by some miracle how would they pass through the Channel and North Sea fleets? And then how would they land enough soldiers and supplies fast enough to break the British militia and army. This home defense was not of too high quality but it was large, add to that the likely French numerical and logistical inferiority and it is safe to say that the invasion was next to impossible.
*Inferior is not straightforward in this case. The British had better gunnery, discipline and overall design and maintenance but the French ships had heavier broadsides, more cannons and were more resilient. The Battle of San Domingo and the French ship ''Imperial'' are perfect examples of what these heavy ships could do and how difficult they could be to take on.