Problems with Operation Sealion

1. The Royal Navy was vastly superior the the Kriegsmarine:
   
   British ships available for anti-invasion duties outnumbered the German Navy (Kriegsmarine) at least 5:1 in every category of large vessel. Additionally, the Royal Navy had access to many smaller craft such as sloops, minesweepers, trawlers, etc., that while not particularly useful against warships, would probably have been able to cause havoc against the Rhine barges that the Germans planned to use to transport their landing force.
   
   The standard argument that if the Germans had gained air superiority they would have been able to sink the British vessels does not really stand up to much scrutiny. During the Dunkirk evacuation, despite having control of the air for long periods, and despite the ships spending a lot of time stationary in the harbour (loading), the Luftwaffe was able to sink only 4 of the 39 Royal Navy destroyers which took place in the operation.
   
   Additionally, the Germans hoped to use submarines and mines to prevent the Royal Navy from entering the Channel. Even if they had succeeded with this, the Royal Navy already had 17 destroyers and 3 light cruisers based within the Channel. The Germans had no real plan for dealing with these ships, other than that their troops on their barges should open fire on any unidentified ships!
   
   HMS Prince of Wales:
   
   
2. The Luftwaffe was inadequate for the tasks required of it:
   
   The German plan demanded rather a lot from their airforce. The Luftwaffe was expected to:
   
   
   • Gain air superiority over the RAF.
   • Prevent the Royal Navy from entering the English Channel and interfering with the invasion barges.
   • Act as flying artillery for the German troops in England (who were not bringing much actual artillery with them).
   • Prevent movement of British Army reinforcements by bombing railroad lines.
   • Bomb London to cause a mass exodus of refugees, thus clogging the roads.
   
   The ambitiousness of these goals can be realized when one considers the fact that the total number of Spitfires and Hurricanes available to the RAF, and the number of Messerschmitts available to the Luftwaffe, were about equal (although the Germans didn't realize this at the time) - and that British were actually producing new fighters more quickly than the Germans. An additional British advantage is that they would be mostly flying over home territory (which meant more time in the air, and a higher chance that pilots who parachuted from their aircraft would be able to fight again), whereas the Germans would not.
   
   Messerschmitt BF-109E:
   
   Even if the Germans had managed to achieve air superiority over Southeast England, that would not have been the end of their troubles. In this eventuality, the British had plans to withdraw their fighters to the Midlands where they would have been able to continue the fight out of range of German fighters. Furthermore, RAF Bomber Command would surely not have remained inactive, but would most likely have been bombing the German invasion barges - and defending them from an attack would have been yet another task for the overstretched Luftwaffe.
   
   
3. German invasion barges were inadequate:
   
   Lacking purpose-built invasion craft, the Germans planned to use barges from the Rhine and elsewhere to carry their landing force to England. However, these craft were flat-bottomed and unsuitable, liable to sink, in even slightly rough seas: in fact, many of the craft could have been sank by merely be the wake of passing fast destroyer!
   
   Crewing the barges was also a major problem. The Kriegsmarine estimated at least 20,000 extra crew would be required to man these barges. After stripping men from its warships (which surely would have damaged their operational efficiency), as well as finding every other person with nautical experience in other military branches, or in civilian life, they were able to rustle up 16,000: 4,000 less than the minimum required.
   
   German invasion barges being assembled in Boulogne, France:
   
   The Germans concluded that they would be unable to bring heavy equipment (such as artillery) with them, and would have to improvise. Nevertheless, since the army used horses for a variety of purposes, they planned to bring 4,000 horses with the first wave of the invasion fleet. To avoid the difficulty of loading horses on barges, they planned to place the horses on rafts towed by the barges (despite the fact that many of the rafts sank during tests). The barges themselves would be towed by tugs (two barges per tug), at would take up to 30 hours to cross the Channel.
   
   Even this was not the end of the problems: the Germans planned for the barges to cross the Channel in columns, then for them to sail parallel to the coast until in a line formation, and then for the barges to turn again and advance towards the coast all at the same time. All of this was supposed to happen at night coordinated by loud hailers, without any rehearsals, and within insufficient numbers of crew with nautical experience.
   
   
4. The invasion force was inadequate to defeat the British Army:
   
   While it is true that the British Army was depleted after the debacle in France, they still had significant forces, including a fair amount artillery. The Germans on the other hand planned to bring no artillery with them, and would have struggled to overcome even antiquated obstacles such as the Royal Military Canal (completed in 1809) or Martello towers (also dating to the early 19th century).
   
   
5. Resupply would have been problematic:
   
   Obviously the German invasion force would soon be in trouble unless it could be resupplied. For this purpose, the German's needed to capture a port, and they decided on Dover. However, the port was well-defended by the British, and as if to compound their problems, the Germans planned to make their parachute drop more than 10 miles (16 kilometers) from the port.