Operation Sealion

Discussions on High Command, strategy and the Armed Forces (Wehrmacht) in general.
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Richard Anderson
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Re: Operation Sealion

#121

Post by Richard Anderson » 28 Dec 2019, 18:22

Yet again, and this repititive ignoring of simple facts is becoming annoying, the German crossing is at night. The Luftwaffe had no night naval air attack capability.
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Re: Operation Sealion

#122

Post by glenn239 » 28 Dec 2019, 18:34

Richard Anderson wrote:
27 Dec 2019, 22:19
Nonsense. To repeat, the KM required at least a half-moon for maneuvering visibility, which restricts the days to: Full Moon – 16 September to Third Quarter Moon – 24 September and First Quarter Moon – 8 October to Full Moon – 16 October. Visibility requirements also meant that anything more than a heavy haze would like result in cancellation as would anything more than a moderate sea or rain. It was the weather conditions that could not be predicted and, given the starting conditions, that meant the only possible September days were 21-24 September, the earlier days were all squally or stormy, forcing the cancellation of S-Boot every day 16-20 September and by Z-Boot on 19 September.
Hitler was the sole authority that could cancel Sealion once the countdown started. Given Hitler's known willingness to shirk personal responsibility for making the attack, I find your argument that he would seize upon even moderately adverse weather conditions to be compelling. That is to say, Hitler seemed to be seeking any reason to avoid ordering an attack he would be solely responsible for in its failure, so given his historical lack of fibre, I can see some mist being seized on as a handy excuse to cancel. That being stated, had it been the opposite case, that Hitler was eager to launch Sealion and unwilling to listen to his navy, I would think it highly unlikely that light rain or some sea mist would deter matters. A bad weather forecast or high sea state? Yes. But mist or light rain? Highly doubtful. Just my opinion.
Correct. So there is no similarity with the "examples" in the Bay of St Malo.
The tactical impact of coastal guns on Allied and German operations would be similar to operations in the narrows of the Channel. That is, RN forces would avoid closing inside 10,000 yards of coastal guns unless the situation warranted, and German forces would attempt in many cases to move towards coastal batteries when threatened.

Nope. Six U-Boot and 20 S-Boot were to deploy off Dover to "protect" the mine barriers (such as they were). Some of the Z-Boot and T-Boot were employed as fast minelayers and to escort the minelayers laying the mines, which were supposed to already be in place by the time the Gelietzug sortie. Nine more U-Boot were to be placed at the opposite end of the Channel off Southampton and Plymouth and with the rest of the Z-Boot and T-Boot would be the sole barrier to attacks from the western British ports.
If the German minelayers were not intercepted by RN forces which drove them off and then covered RN minesweeping efforts, then the mine barriers are in place and the RN is blocked by minefields from its approach to Sealion by the forces you describe. But if the RN engaged the minelayers and their escorts to break through this barrier, then the RN is in battle with the German minelaying forces, not the invasion barges.

German minesweepers by the dozens would be ahead of the main convoys seeking to sweep mines in the approach channels. RN warships moving towards German forces would be running into German minesweepers and engaging them because the incredible confusion of the situation would cause any number of RN officers - operating without detailed intelligence - to tend to hotly attack the first thing they encountered.

German Siebel ferries (two dozen of them) and dozens of sloops and other aux. escorts would presumably impose themselves between approaching RN forces and the barge columns using shore based radars that are tracking the movement of RN warships. These forces will cause yet more RN warships to engage them due to a lack of general situational awareness.

German motor boat formations - operating at a distance from the barge columns would be likely to collide with, and attract the attention of, major RN elements approaching from the west.

Some portion RN forces will sweep aside these impediments and engage the barge columns.
The reality of the experience of U-Boot in shallow waters and in all subs in such coastal operations during the war means they are likely to have nearly zero effect.
RN warships returning from night engagements will need to enter port quickly to replenish shell supplies as quickly as possible. They will be vulnerable to U-boat attacks as they enter and exit port. RN warships at sea will be relatively invulnerable to U-boats with the possible exception of ships damaged by air attacks, or slow battleships committed to the Channel.
BTW, the Germans had no "aux. sloop type escorts". They had Kriegsfischkutter, which typically were around 100 tonnes, 24 meters long, 6.5 meters wide, with a top speed of about 9 knots and armed with a single 3.7cmn and 2cm gun.
As per previous discussions at some length, the data from WW2 battles seems to confirm the theory that anything - no matter how small or how slow - with guns willing to fire in night combat would draw precious time and ammunition. Given the scale of Sealion, the RN was not in a position to lightly give up either. That, IMO, is the risk, that in the confusion of night combat, the RN's time and energy is absorbed in the wrong activities against the wrong targets.


Sorry, I did not refuse, but I was uninterested, since I have no intention of doing a validation exercise for you. I'm retired from that business.
The file was offered FYI, not as part of any validation exercise. The only thing I've requested is additional information on shell expeditures and better details on coastal artillery actions. You were able to provide a bit of both, and thank you.

RN destroyers did not regularly do convoy duty, except for the old V&W class that had been rebuilt as convoy escorts. Convoy escort was the duty of sloops, frigates, corvettes, and the like.
RN destroyers did not do Atlantic SLOC duties in 1940?
Whatever floats your boat, but that is a data-less construct of your mind. I'm inclined to think it is something else. Radar increased the distance they could detect vessels, but for gunfire purposes it was late 1944 before the combination of Mark 37 Director, Mark 12 Radar, and Mark 22 fire control selsyned to the USN 5"/38 created a lethal surface gunnery system...but the British never deployed it IIRC during the war.
The laws of ballistics and physics and the characteristics of naval gunfire under various conditions, the capacity of search radar to increase the search-acquire-attack cycle - all these things inherent to combat effectiveness of warships using guns in WW2 - these are not the act of me floating a boat. The later war data does not suggest a level of lethality in warship attacks of a scale to decide Sealion in a night action. Whether or not the disruptive effects of such combat could do so - that's the more interesting question (IMO).
There is no evidence the British would use massive formations against the German convoys; I am not sure where you get that from? They would be task organized as they did at Crete, typically light cruisers leading destroyer flotilla.
From the Crete example, the RN invasion reaction might therefore be about 15 such formations each formation accounting for something like 10 kills, or 150 kills in total out of 3,500 targets that could theoretically be engaged?
Why would they need to "hunt" coastal transports? The hundreds of picket boats on station provide one means of tracking, the Chain Home Low system another.
The RN warships have no radar and they are seeking blacked out tiny targets hiding behind escorts and smoke screens in the Channel. In terms of Chain Home, of what possible use would that be, other than to inform RN warships that there is a giant blob of targets scattered between Dover and Isle of Wight? The land based radar factor is clearly in favor of the KM, which can track approaching RN warships, is it not?

Also, with Chain Home, it will go off the air as German troops land and seize the stations - will the RAF have Chain Home available afterwards, or is it fighting blind in key zones in the Channel thereafter?
BTW, what "air attack" are they going to be under at night? The Gelietzug were supposed to be in place landing troops at first light.
Level bombing and 20mm strafing attacks at night. Not dive bombing. Coastal artillery could illuminate RN warships detected by radar with star shells, and Luftwaffe aircraft should be able to attack them on that basis, or simply by attacking them when they fire their guns. Twin engine types for the most part, not single engine. Other twin engine types would presumably seek to attack RN ports with bombs and mines, seeking to catch replenishing ships moving in and out of port. The effect of such attacks would, of course, largely be of the harassing variety, but the point is that even harassing attacks that do not cause attrition can detract significantly from the power of the RN's punch in the Channel.
Last edited by glenn239 on 28 Dec 2019, 18:54, edited 2 times in total.


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Re: Operation Sealion

#123

Post by glenn239 » 28 Dec 2019, 18:45

Richard Anderson wrote:
28 Dec 2019, 18:22
Yet again, and this repititive ignoring of simple facts is becoming annoying, the German crossing is at night. The Luftwaffe had no night naval air attack capability.
As per the generally agreed sketch of the discussion, the RN will collide with elements of Sealion during a night battle. The effect of this collision might be to sink somewhere in the order of 75-200 out of 3,500 vessels displayed, and to disperse, disorganize, or confusion, a significant slice of the remainder. Some of the Sealion invasion - perhaps 50% - will reach shore and land, and the British army will proceed to repulse some of these invaders and collapse or commit unbelievable errors elsewhere. Come dawn, the issue will be in doubt as the Germans start to direct dispersed invasion forces - perhaps 50% of the original total of Sealion's landing forces - to the landing areas where the attackers succeeded and are now trying to break out. The RN will be forced into a massive daylight battle against strong elements of the Luftwaffe acting at maximum sortie rate, with the RAF in full support.

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Re: Operation Sealion

#124

Post by Richard Anderson » 29 Dec 2019, 05:02

glenn239 wrote:
28 Dec 2019, 18:34
Just my opinion.
Yep.
The tactical impact of coastal guns on Allied and German operations would be similar to operations in the narrows of the Channel. That is, RN forces would avoid closing inside 10,000 yards of coastal guns unless the situation warranted, and German forces would attempt in many cases to move towards coastal batteries when threatened.
The "narrows of the Channel"? Seriously, have you bothered to look at a map? Twenty-three miles, give or take, from Calais to Dover. The extreme range of German coastal guns barely reach one-quarter of the way.

If the German minelayers were not intercepted by RN forces which drove them off and then covered RN minesweeping efforts, then the mine barriers are in place and the RN is blocked by minefields from its approach to Sealion by the forces you describe. But if the RN engaged the minelayers and their escorts to break through this barrier, then the RN is in battle with the German minelaying forces, not the invasion barges.
Nope. The mine barrier program was supposed to be completed before the invasion launched. The KM correctly noted that the problem was the minefields would only remain effect so long as the British could be prevented from clearing them. That meant the covering forces, the Z-Boot and T-Boot needed to be much stronger, especially given they were an integral part of the minelaying force.
German minesweepers by the dozens would be ahead of the main convoys seeking to sweep mines in the approach channels. RN warships moving towards German forces would be running into German minesweepers and engaging them because the incredible confusion of the situation would cause any number of RN officers - operating without detailed intelligence - to tend to hotly attack the first thing they encountered.
The German minesweepers, the M-Boot and R-Boot, were actually tasked as escorts, troop transports for the coup de main forces, and minesweeping, at the same time, virtually guaranteeing none of the operations would be done well.
German Siebel ferries (two dozen of them) and dozens of sloops and other aux. escorts would presumably impose themselves between approaching RN forces and the barge columns using shore based radars that are tracking the movement of RN warships. These forces will cause yet more RN warships to engage them due to a lack of general situational awareness.
The Siebel ferries were actually tasked to transport II./Luftwaffe-Flak-Regiment 14, I./Luftwaffe-Flak-Regiment 26, I./Luftwaffe-Flak-Regiment 3, and I./Luftwaffe-Flak-Regiment 36, one each assigned to Transportflotte B, C, D, and E, thus separated, like their parent Flotte, by dozens of miles. They are departing in four groups from some dozen ports scattered across about 250 miles from Rotterdam to Le Havre.
German motor boat formations - operating at a distance from the barge columns would be likely to collide with, and attract the attention of, major RN elements approaching from the west.
What "motor boat formations"? Each Flotte consisted of a number of Geleitzug (steamers towing unpowered barges) or Schleppverband (powered barges towing unpowered barges). Gelitzug 3 from Antwerp also had 14 "motor boats" as auxiliaries, IIRC transporting parts of the Brandenburg coupr de main force.
Some portion RN forces will sweep aside these impediments and engage the barge columns.
They are one and the same.
RN warships returning from night engagements will need to enter port quickly to replenish shell supplies as quickly as possible. They will be vulnerable to U-boat attacks as they enter and exit port. RN warships at sea will be relatively invulnerable to U-boats with the possible exception of ships damaged by air attacks, or slow battleships committed to the Channel.
Um, none of the U-Boot were tasked to watch British ports. They tried that with the Typ-II, VII, and IX in the Norwegian campaign and the result was pretty grim...for the Germans. The U-Boot were tasked as picket lines, 6 off Dover covering the minefields (such as they were) and 9 covering the western end of the Channel. Another 5 were tasked as pickets, without clearly defined locations insofar as I have found, which might be related to the simple fact that only 19 operational U-Boot (aside from Ducks) were available, 16 at the start of September and 3 joining during the month.
As per previous discussions at some length, the data from WW2 battles seems to confirm the theory that anything - no matter how small or how slow - with guns willing to fire in night combat would draw precious time and ammunition. Given the scale of Sealion, the RN was not in a position to lightly give up either. That, IMO, is the risk, that in the confusion of night combat, the RN's time and energy is absorbed in the wrong activities against the wrong targets.
What "wrong targets"? Let's say Geleitzug 1 out of Ostende is encountered...if the Germans achieved their plan, then that is 9 minesweepers, M1601-1609 (converted fishing steamers), escorting 15 steamers, each towing 2 barges and accompanied by 1 motor boat as an auxiliary.
The file was offered FYI, not as part of any validation exercise. The only thing I've requested is additional information on shell expeditures and better details on coastal artillery actions. You were able to provide a bit of both, and thank you.
You're welcome.

RN destroyers did not do Atlantic SLOC duties in 1940?
No, not regularly. The "destroyers" regularly used were the aging Shakespeare-class (3), Scott-class (6), old R-class (1), old S-class (6), and especially the V&W-class (58) many of which were de-boilered to increase endurance. Some DD did do convoy duty. On a typical day, 16 September 1940, there were 8 DD: Veteran (left Harwich 17 Sep), Witherington (left Plymouth 16 Sep), MacKay (left Plymouth 15 Sep), Hurricane (left Liverpool 15 Sep), Winchelsea (left Liverpool 13 Sep), Warwick (left Liverpool 11 Sep), Witch (left Belfast 17 Sep), Wanderer (left Londonderry 16 Sep), 2 DE: Vivien (left Rosyth 16 Sep), Wolfhound (left Rosyth 15 Sep), and 1 TB: G.15 (NL) (left Plymouth 16 Sep) on "patrols, escorting convoys, etc".
The laws of ballistics and physics and the characteristics of naval gunfire under various conditions, the capacity of search radar to increase the search-acquire-attack cycle - all these things inherent to combat effectiveness of warships using guns in WW2 - these are not the act of me floating a boat. The later war data does not suggest a level of lethality in warship attacks of a scale to decide Sealion in a night action. Whether or not the disruptive effects of such combat could do so - that's the more interesting question (IMO).
Whatever floats your boat.
From the Crete example, the RN invasion reaction might therefore be about 15 such formations each formation accounting for something like 10 kills, or 150 kills in total out of 3,500 targets that could theoretically be engaged?
Generalizing the effects from two instances out of "about 15 such" is an invitation for analytical disaster.
The RN warships have no radar and they are seeking blacked out tiny targets hiding behind escorts and smoke screens in the Channel. In terms of Chain Home, of what possible use would that be, other than to inform RN warships that there is a giant blob of targets scattered between Dover and Isle of Wight? The land based radar factor is clearly in favor of the KM, which can track approaching RN warships, is it not?
No, the RN warships do have radar, some of them at least. How do you "hide" a 3,500 ton steamer behind a 100 ton fishing boat minesweeper "escort"? What "smoke screens"? How do they generate them? Where is the planning for them? How does that affect the critical visibility component of the KM plan?

Methinks there is a different kind of smokescreen being employed here.
Also, with Chain Home, it will go off the air as German troops land and seize the stations - will the RAF have Chain Home available afterwards, or is it fighting blind in key zones in the Channel thereafter?
Sure, if you assume the coup de main forces execute things perfectly when they transfer from their motorboats to Sturmboot, land on the beach, walk through the British beach defenses and those of the stations, and then capture them.
Level bombing and 20mm strafing attacks at night. Not dive bombing. Coastal artillery could illuminate RN warships detected by radar with star shells, and Luftwaffe aircraft should be able to attack them on that basis, or simply by attacking them when they fire their guns. Twin engine types for the most part, not single engine. Other twin engine types would presumably seek to attack RN ports with bombs and mines, seeking to catch replenishing ships moving in and out of port. The effect of such attacks would, of course, largely be of the harassing variety, but the point is that even harassing attacks that do not cause attrition can detract significantly from the power of the RN's punch in the Channel.
What "level bombing and 20mm strafing attacks at night" are those? Where is the planning for them? The practice for them? Who executes them? Against what?

Yeah, smokescreens, red herrings, and shotgun responses are starting to dominate this conversation.
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Re: Operation Sealion

#125

Post by Knouterer » 29 Dec 2019, 13:17

Some more data:
From 1 July to 9 August 1940 the Kanalkampffuehrer, Oberst Johannes Fink, dispatched 1,300 anti-shipping sorties, mainly by Do 17s and Ju 87s, and they managed to sink 28 ships totalling 54,109 GRT.

One ship sunk per 46 sorties. But these were slow-moving defenseless (except for a Lewis MG or two) colliers and other small cargo vessels. Against warships going 25 knots or so, manoeuvring and shooting back, the success rate would certainly be lower.

The RN ships sunk by the Luftwaffe in 1940-41 were mostly stationary, or restricted in their movements in some way, and/or out of ammunition.
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Re: Operation Sealion

#126

Post by Knouterer » 29 Dec 2019, 13:19

Regarding radar in the Royal Navy:

Work on naval radar (RDF) had begun in 1935 and the first operational set, Type 79Y, was installed on the cruiser Sheffield in August 1938. The first production set, Type 79Z, was installed on the anti-aircraft cruiser Curlew a year later, and about a hundred were made. This was an aircraft warning set, but with some surface warning capability as well. Destroyers were equipped with the Type 286 from mid-1940 (HMS Cossack had one installed in May), which had a fixed masthead antenna that scanned only forward of the ship and had a limited detection range of about 20 miles for aircraft and less than half that for surface targets. It was replaced by improved versions from 1941. Destroyers also had powerful searchlights and star shells (illuminating rounds) for their main guns. In the 1930s the Navy had spent much time training in night fighting, and this training paid off during nocturnal engagements with the Italian navy later in the war, such as the Battle of Cape Matapan in March 1941.
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Re: Operation Sealion

#127

Post by William_2018 » 30 Dec 2019, 14:37

Would the invasion only have to be partially enabled before it became successful? i.e. Would a full scale invasion even be necessary to achieve the same result with Britain capitulating early? e.g. France surrendered when only a fraction of the country had been invaded. Does the end result rest with the military operation, or with the political forces at play in Britain working with Germany to achieve peace before the invasion took its toll? Would Churchill ever concede and accept peace with Germany?

Hypothetical Churchill surrender speech



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Re: Operation Sealion

#128

Post by aurelien wolff » 03 Jan 2020, 14:21

they had to get air superiority before landing wich they didn't have,also wasn't the operation postponed a lot?

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Re: Operation Sealion

#129

Post by T. A. Gardner » 03 Jan 2020, 22:41

Richard Anderson wrote:
28 Dec 2019, 18:22
Yet again, and this repititive ignoring of simple facts is becoming annoying, the German crossing is at night. The Luftwaffe had no night naval air attack capability.
Except, as has been discussed in the "What if" section at length, the crossings would take anywhere from 24 to 72 hours + depending on the port of departure and ability of the convoy to move with tides, sea state, and currents. That means they'll be in daylight for at least part of the crossing. At night, the RN could easily use star shell and other illumination rounds to light up targets and open fire on them.
Given the poor level of training in things naval, I can see lots of nervous German crews and troops on barges with improvised weapons mountings opening fire on their own ships in accidental amicide events, particularly once some RN ships open fire on them.

Smoke screens, as one person suggests? Not likely. First, you'd need wind conditions to be nearly calm. Any sort of stiff breeze / wind above about 10 to 15 knots and your smoke screen is in Spain in a matter of minutes (yes that's an exaggeration to make a point). Also, given the crossing time, it's not going to be possible to keep any sort of smoke screen going for days. That's totally unrealistic.

The whole crossing is likely to be a cluster f.... to the max.

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Re: Operation Sealion

#130

Post by Knouterer » 04 Jan 2020, 11:34

It is clear that even without enemy interference a whole lot of things would have to go just right for the invasion to have the slightest chance of success, and any delay or mishap would have thrown the whole thing into confusion.

The tide comes up from the Atlantic towards Dover twice per day and flows back twice a day, in other words, the direction of the current changes every six hours. As the barge convoys would make only five knots (hopefully ...) it was important that they would have to struggle against the current for the shortest possible time.

This map from Schenk's book shows the planned progression of the barge convoy bound for Rye Bay (landing beach C) from Calais. The fifty transports (about 4,000 GRT on average) carrying most of the vehicles and artillery for this landing force (7th Infantry and 1st Mountain Divisions) would come from Antwerp.

The barge convoy would assemble off Calais on S-1, which would take from 10h00 to 17h00, according to the German plans. In full view of interested parties on the cliffs of Dover with powerful binoculars and telescopes, weather permitting of course.

As the maps shows, the convoy, about 15,000 meters long, accompanied by minesweepers and Vorpostenboote, would then move SW, passing to the south of The Ridge, a dangerous sand bank in mid-Channel. Initially it would move against the current, but from S-time minus 9 hours (which would be about 22h00 German time and 21h00 British time (GMT plus 1h)) it would help them along. From about S-4h the tide would turn again but by S-2h the convoy would have reached the "starting line" (indicated by boats with different coloured lights) from where it would execute a 90° turn and head for the beaches, which the advance detachments in little wooden Sturmboote and rubber boats would hit at S-time, 07h00 (06h00 British time), about an hour and a half after high water (supposing the date to be around 24-26 Sept.).
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Re: Operation Sealion

#131

Post by Richard Anderson » 04 Jan 2020, 17:58

Knouterer wrote:
04 Jan 2020, 11:34
It is clear that even without enemy interference a whole lot of things would have to go just right for the invasion to have the slightest chance of success, and any delay or mishap would have thrown the whole thing into confusion.
Yep, pretty evident, except for those who believe in the SEELÖWE cakewalk.
The tide comes up from the Atlantic towards Dover twice per day and flows back twice a day, in other words, the direction of the current changes every six hours. As the barge convoys would make only five knots (hopefully ...) it was important that they would have to struggle against the current for the shortest possible time.
Yep, note that means Glenn's notion of the Schleppverband executing a Gefechtskehtwendung to "shelter" under the German "coastal artillery" lining the French shores if the RN intervenes is pie-in-the-sky.
This map from Schenk's book shows the planned progression of the barge convoy bound for Rye Bay (landing beach C) from Calais. The fifty transports (about 4,000 GRT on average) carrying most of the vehicles and artillery for this landing force (7th Infantry and 1st Mountain Divisions) would come from Antwerp.
Yep, note that if Schleppverband 3 from Calais of Transportflotte B is destroyed, dispersed, or forced to shelter, then Geleitzug 3 from Antwerp has little means of executing the landing by itself. It is mostly the combat support, service support, and rear command elements of the division...the tail rather than the teeth.
The barge convoy would assemble off Calais on S-1, which would take from 10h00 to 17h00, according to the German plans. In full view of interested parties on the cliffs of Dover with powerful binoculars and telescopes, weather permitting of course.
Yep, note that the weather, like the moon and tide, has to permit or the plan cannot be executed.
As the maps shows, the convoy, about 15,000 meters long, accompanied by minesweepers and Vorpostenboote, would then move SW, passing to the south of The Ridge, a dangerous sand bank in mid-Channel. Initially it would move against the current, but from S-time minus 9 hours (which would be about 22h00 German time and 21h00 British time (GMT plus 1h)) it would help them along. From about S-4h the tide would turn again but by S-2h the convoy would have reached the "starting line" (indicated by boats with different coloured lights) from where it would execute a 90° turn and head for the beaches, which the advance detachments in little wooden Sturmboote and rubber boats would hit at S-time, 07h00 (06h00 British time), about an hour and a half after high water (supposing the date to be around 24-26 Sept.).
Yep, so say Aurora and Cardiff of 2 CS, along with Brilliant, Icarus, Impulsive, Intrepid, Campbell (D21), Venetia, Vesper, Vivacious, and Walpole from 21 DS, perhaps with Cattistock, Eglinton, Holderness, Garth, Hambledon, Quorn, Vanity, Vimiera, Wallace, Westminster, Winchester, and Wolsey from Sheerness and Chatham, two light cruisers, nine destroyers, and twelve destroyer escorts and sloops, as well as three MTB are dispatched to intercept and encounter the escort of five minesweepers and twelve R-Boot, and 20 converted trawlers and fishing boats, dispersed along a fifteen-kilometer long convoy. What might the result be I wonder?

Note also that with ten-plus hours notice, the RN would have plenty of time to sortie 18 CS, 5 DF, and 16 DF from the Humber and Harwich, so three more light cruisers and eleven destroyers, with eleven MTB, which would probably encounter the Minesperre covering force of four T-Boot and twenty S-Boot.
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Re: Operation Sealion

#132

Post by glenn239 » 04 Jan 2020, 18:19

Knouterer wrote:
29 Dec 2019, 13:17
Some more data:
From 1 July to 9 August 1940 the Kanalkampffuehrer, Oberst Johannes Fink, dispatched 1,300 anti-shipping sorties, mainly by Do 17s and Ju 87s, and they managed to sink 28 ships totalling 54,109 GRT.

One ship sunk per 46 sorties. But these were slow-moving defenseless (except for a Lewis MG or two) colliers and other small cargo vessels. Against warships going 25 knots or so, manoeuvring and shooting back, the success rate would certainly be lower.
Sounds about right, so the question is how many anti-ship sorties most of the Luftwaffe could generate 30 miles from a first class LW air base network during an all-out daylight air sea battle in which scattered Sealion forces were seeking to reinforce successful landings and the RN/RAF was throwing all-in against them. If the answer is the 1,300 anti-ship sorties as per your statistic, then at 200 sorties per warship sunk, that would be about 7 RN destroyers and cruisers sunk. If the answer were to be 3,500 sorties, then that would be about 17 warships sunk.

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Re: Operation Sealion

#133

Post by histan » 04 Jan 2020, 21:12

There is a bit of a problem here.

The main anti-shipping aircraft of the Kanalkampf was the Ju-87, dive bomber.

Since the German army would land without artillery and there would be no naval gunfire support, the infantry would have to rely on the Luftwaffe to provide the support normally provided by artillery.

The Ju-87s would be required to spend the day of the landings attacking previously identified land targets, for example artillery batteries, that could hold up the infantry.

It is highly unlikely that there would be any Ju-87 sorties available for anti-shipping operations.

The same is true of the medium bomber force.

The number of anti-shipping sorties, not counting mine laying, is likely to be in the tens rather that the thousands.

The Luftwaffe didn't have enough aircraft to meet all the demands that might be placed on them.

Regards

John

PS The Ju-87 strength at 13.08.1940 was 384 with 305 serviceable. So even with a sortie rate of 4 per aircraft on strength per day it would require the whole Ju-87 force to sink 7 RN destroyers and cruisers.

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Re: Operation Sealion

#134

Post by Aber » 05 Jan 2020, 11:01

glenn239 wrote:
28 Dec 2019, 18:34

From the Crete example, the RN invasion reaction might therefore be about 15 such formations each formation accounting for something like 10 kills, or 150 kills in total out of 3,500 targets that could theoretically be engaged?
You're using the wrong metric, as you need to factor in the number of targets available. Therefore perhaps 60%+ of available targets, not 10 per formation. :wink:

Knouterer
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Posts: 1661
Joined: 15 Mar 2012, 18:19

Re: Operation Sealion

#135

Post by Knouterer » 05 Jan 2020, 14:12

glenn239 wrote:
04 Jan 2020, 18:19


Sounds about right, so the question is how many anti-ship sorties most of the Luftwaffe could generate 30 miles from a first class LW air base network
What "first class LW air base network"??? By mid-September both the Ju 87 and Bf 109 Geschwader were crammed together in the Pas-de-Calais region, because of their short range. As there were no real airfields there (except one or two small ones), and no time to build any, every more or less level surface of suitable size had to serve, including recently harvested stubble fields, which were muddy when it rained and dusty when it was dry.

Repairs and maintenance had to be carried out in the open, or at best in tents or barns. Of course the Luftwaffe could and did operate under such primitive conditions on many occasions all through the war; nevertheless, in a battle of attrition, as the BoB was, the RAF had a decided advantage in that it operated from "real" airfields with all the necessary infrastructure.

LW bomber units generally operated from real airfields, but those were further back from the coast.
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