It has to do with the loss of men and material if the invasion was ever launched. How many divisions would have been gutted, and how much artillery, tanks and other war material destroyed or captured, assuming the invasion failed?
I'd think the Germans would lose pretty much everything they put on the shore. I can't see them doing a Dunkirk.
I think with more realistic inputs we can probably double and maybe even triple those numbers (I'd be hesitant about going beyond triple just because the chaotic nature of a night action and the large number of targets...). Add in vessels that run for home and vessels that end up scattered to all points of the compass and maybe half the first wave makes it ashore in some very loose approximation to order.Assuming a hit rate expected for long ranged engagements in a short range melee; only considering a relatively small fraction of available British forces (DDs only, ignoring sloops, corvettes, armed trawlers and similar also available); assuming negligible non-combat losses and neglecting smaller caliber weapons... all VERY optimistic for the Germans. That's still something like 5-10% (140-280 out of a nominal 2400 barges plus other vessels?) of all German sealift available for Seelowe destroyed or heavily damaged on a single night.
Tell me how long you think the Germans can sustain such losses before their ability to supply and reinforce the beachhead(s) fails?
I suspect it also translates into 10-20% of the vessels involved in the initial landing and day one reinforcements (given a minimum 24hr round trip time on the shortest routes, putting every vessel out for the landing means no reinforcements for a day after the landing)... Then add vessels engaged with smaller caliber weapons (a good burst of two-pounder should pretty thoroughly wreck a barge; a burst of Vickers 0.5in is marginal on the sinking front but will heavily damage engines, control systems and similar and cause heavy casualties amoungst passengers and crews; a burst of .303 is unlikely to sink or seriously damage a barge but will kill passengers and crew) and a whole disruption side of things (Destroyers ploughing through your formation doesn't do much good for your navigation, likewise deploying smokescreens), I'd suggest total losses are more like 20-30% of the first wave, with probably another 10-20% either forces to turn back or scattered haphazardly along the British coast...
Even taking horribly pro-German estimates (low RN hit rate, only considering main guns on DDs and nothing else) from our resident Sealionophile, the Germans look likely to loose 10% of the first wave sunk/disabled at sea:
I think with more realistic inputs we can probably double and maybe even triple those numbers (I'd be hesitant about going beyond triple just because the chaotic nature of a night action and the large number of targets...). Add in vessels that run for home and vessels that end up scattered to all points of the compass and maybe half the first wave makes it ashore in some very loose approximation to order.
That's before the Germans actually start fighting ashore...
edit: Of cause, given the nature of night actions, odds are individual RN vs barge convoy actions will be all over the place... One convoy arriving intact, the one behind it wiped out, the one 10NM up-channel scattered but taking only moderate losses, the one 10NM down-channel running for home without actually being engaged etc.
It has to do with the loss of men and material if the invasion was ever launched. How many divisions would have been gutted, and how much artillery, tanks and other war material destroyed or captured, assuming the invasion failed?