Operation Sea Lion (wargame)

Operation Sea Lion was a major wargame conducted at Royal Military Academy Sandhurst in 1974. Its aim was find out what might have happened had Nazi Germany launched Operation Sea Lion, their planned invasion of southeast England during World War II, on 22 September 1940. The wargame was organized by the Daily Telegraph and Dr Paddy Griffith from the Department of War Studies at Sandhurst. The German umpires were General Adolf Galland (air), Admiral Friedrich Ruge (naval) and General Heinrich Trettner (land). Their respective British counterparts were Air Chief Marshal Christopher Foxley-Norris, Rear Admiral Teddy Gueritz and Major General Glyn Gilbert. After the game's conclusion, the umpires unanimously concluded that the invasion was a devastating defeat for the German invasion force.

Scenario

The game was played using a scale model of southeast England, the English Channel, and northern France. Available troops and resources were based on known plans from both sides, and weather conditions were based on contemporary British Admiralty records that had, until then, never been published. The scenario assumed that the German military had taken until September to assemble the shipping necessary for a Channel crossing, and that the Luftwaffe had not yet established air supremacy. The Luftwaffe also had to continue to bomb London. As happened historically, the Germans mainly had river barges available as transport ships.

Invasion

The German attack was launched at dawn on 22 September 1940 and consisted of 8,000 airborne troops and 80,000 infantry landed in amphibious operations. The attack went reasonably well for the first 24 hours, although the Germans lost about 25% of their (unseaworthy) barges which were being used to ferry the forces across the channel. During this 24 hour period the Royal Air Force lost 237 aircraft (about 23% of its fighting strength), the Luftwaffe losses amounted to 333, also about 23% of its aircraft. Naval engagements were indecisive at this stage as the Royal Navy was still assembling its main destroyer fleet to attack. The larger ships of the Home Fleet (including battleships, heavy cruisers and aircraft carriers) were not to be committed due to the risk of air attack.

Over the next two days the Germans managed to advance a dozen or so miles inland and captured the port of Folkestone. However, once the British and Commonwealth forces were moved to fully engage in the battle the advance halted. At this stage the Germans had few tanks and only light artillery, furthermore an increasing shortage of ammunition was slowly forcing them back towards the sea. The Germans asked "Hitler" if the bombing of London could stop and the planes used to attack British ships instead but the request was denied. At dawn on 24 September the second German landing, which was to include tanks and heavy artillery as well as supplies and men, was intercepted by the Royal Navy's destroyers—65% of the barges were sunk. After this the final German surrender was inevitable.

Conclusion

The German navy`s relative weakness, combined with the Luftwaffe`s lack of air supremacy, meant it was not able to prevent the Royal Navy from interfering with the planned Channel crossings. The Navy's destruction of the second invasion wave prevented resupply and reinforcement of the landed troops, as well the arrival of more artillery and tanks. This made the position of the initially successful invasion force untenable; it suffered further casualties during the attempted evacuation. Of the 90,000 German troops who landed only 15,400 returned to France. 33,000 were taken prisoner, 26,000 were killed in the fighting and 15,000 drowned in the English Channel. All six umpires deemed the invasion a resounding failure.

Notes

Short summary of the Sea Lion wargame.
Information from "Operation Sealion" by Richard Cox ISBN090272617X

The scenario for the 1974 Staff College wargame has been published by John Curry as part of the History of Wargaming Project. See Paddy Griffith's Sprawling Wargames link and photos from the 1974 wargame can be found at link