Operation Sea Lion: The Invasion Itself

[patch_g]

For interest's sake, here's a series of pictures of the 1974 wargame
http://www.wargaming.co/books/paddysprawling/articles/sealion.htm
(I had NEVER seen a single wargamer wearing a tie).

I own a copy of Cox's book, found it second-hand years ago, it was what got me into alternate history. An enjoyable read, if you can get a copy, with some useful tables at the back.

I also own Britain Stands Alone
http://www.gmtgames.com/p-255-britain-stands-alone.aspx
and have gamed Sealion a few times. From memory, I don't think the invaders were ever successful. For the Germans, it's always "I have so much land power, but I can't get it to Britain". This game showed me that Sealion wasn't going to work. You can't resupply AND reinforce AND expand the bridgehead fast enough. Even when I took out the naval aspect (Why yes, every RN ship simultaneously broke down), the ports in the invasion zone were captured damaged and kept that way by the RAF. Then the October storms arrived and the supply chain was cut.

 

[MattII]

Did they?

Oh they may have had a few Siebel Ferriers too, but their attempts to build custom landing craft (the Pionierlandungsboot and Marinefährprahm) were not ready in any numbers until 1941.

I dissertated on Sea Lion and IIRC there was enough to fill a chapter on German deceptions and big plans - like the concrete crocodiles - that British intelligence seemed to be believing were a threat IOTL.

And then they would have to do probably several days preparation to have any hope of getting barges across safely, which would key the RN as to exactly where the Invasion was coming.

Sorry for the miscommunication.

You are the one saying that Sandhurst is the definitive exercise so that we need not bother with another one.

No I'm not, I'm simply pointing you at a published work that has a more detailed analysis of said wargame than anything published online, in reference to your statement that you could only find a wikilink reference.

A better summary, but still no explanation for any of the gaming results. It's not clear if the judges imposed restrictions on the British players to clear the Channel for the first assault, but it looks like they forced them to go for the diversionary force. It seems apparent that the judges interfered with the German players in the guise of "Hitler" - preventing them from properly employing their available airpower, and then imposing a delay on the 2nd wave to time it to arrive at dawn straight into the arms of the waiting RN CL/DD forces when it appears the German players did not want to do it that way.

That is a limitaion, but not necessarily a totally arbitrary one, given that the German leader at the time would actually be Hitler.Remember, the Luftwaffe didn't want to start terror-bombing in the first place, they were only ordered to do so by Hitler.

The modelling looks to have been something like 1 bomber sortie = 1 barge sunk and 2 fighter sorties = 1 aircraft shot down - if so, this is too crude.

Crude, yes, but with less than a dozen gamers, and in the days when Computers were working at kilobyte speeds and had, at best, megabyte-sized memories, some compromises had to be made.

Perhaps if you think the game is faulty you could come up with a better way, write the code and that yourself.

 

[Glenn239]

For interest's sake, here's a series of pictures of the 1974 wargame
http://www.wargaming.co/books/paddysprawling/articles/sealion.htm
(I had NEVER seen a single wargamer wearing a tie).

I own a copy of Cox's book, found it second-hand years ago, it was what got me into alternate history. An enjoyable read, if you can get a copy, with some useful tables at the back.

I also own Britain Stands Alone
http://www.gmtgames.com/p-255-britain-stands-alone.aspx
and have gamed Sealion a few times. From memory, I don't think the invaders were ever successful. For the Germans, it's always "I have so much land power, but I can't get it to Britain". This game showed me that Sealion wasn't going to work. You can't resupply AND reinforce AND expand the bridgehead fast enough. Even when I took out the naval aspect (Why yes, every RN ship simultaneously broke down), the ports in the invasion zone were captured damaged and kept that way by the RAF. Then the October storms arrived and the supply chain was cut.

That picture is perfect. There's no grid pattern in the sea or over the land - that means the naval and air elements were abstracted. The German diversion raid is off map, so also an abstraction. The map of southern England is also fairly crude. The subsequent pictures show more detailed maps.

Blocks = 1 division. In the final two pictures, it shows the German 9 divisional blocks all pinned on the coast - not apparent from the landing pictures why this was so.

Map looks to show no fog of war for either side.

Overall, looks pretty crude.

 

[MattII]

You know of another wargame played with that scenario in mind?

 

[Garrison]

That picture is perfect. There's no grid pattern in the sea or over the land - that means the naval and air elements were abstracted. The German diversion raid is off map, so also an abstraction. The map of southern England is also fairly crude. The subsequent pictures show more detailed maps.

Blocks = 1 division. In the final two pictures, it shows the German 9 divisional blocks all pinned on the coast - not apparent from the landing pictures why this was so.

Map looks to show no fog of war for either side.

Overall, looks pretty crude.

So at what detail level will the Germans win then?

 

[sitalkes]

You know of another wargame played with that scenario in mind?

Decisive Battles the Blitzkrieg from Warsaw to Paris includes a Sealion scenario, which you can either play separately or as part of the whole campaign. The sea element is abstracted but even suffering 40% casualties for units just for landing in England and using an as-planned deployment (with delays for the second wave etc) I was able to win as the Germans. You can deploy the German units as you like (within very strict shipping limitations) but I have put a description of how to play the Sealion deployment and plan on their forum.

http://www.matrixgames.com/products...ampaigns:.The.Blitzkrieg.from.Warsaw.to.Paris.

There is also a version of Il-2 Sturmovik called Cliffs of Dover that allows you to fight the air war and some of the ground war. http://store.steampowered.com/app/63970 and http://bobgamehub.blogspot.dk/2012/11/the-raf-campaign-redux-mission-design.html

 

[sitalkes]

Something I've been curious about is what forces could the British bring in from overseas in response to an invasion? The nearest reinforcements are in Canada and the Caribbean.

Another question is, what might the USA have done? I can imagine FDR ordering the Navy in to protect Americans. If they free up British garrisons and ships for the front, oh well, that happens. I also like the idea of US cruisers loaded with Canadian and other Empire troops making high speed runs across the Atlantic.

FDR may have wanted to go to war with Germany, but first he has to get the isolationist Congress to agree, then he has to organise the troops and supplies, then he has to get it across the Atlantic - the last part alone might take three weeks in bad weather. The Germans have to win within a couple of months or they will be fighting in winter and delaying the attack on Russia (plus the RN could have been massively reinforced and the army fully re-deployed by then). If the Americans arrive it's likely to be after Britain has fallen or survived on its own. What help they did send to Britain in 1940-41 they made the British pay through the nose for it, with the result that Britain was bankrupt by 1941. If the British lose, and Britain gets split into a German area and several puppet states, then perhaps the Americans can secretly make a deal with a puppet state and land their troops there (Liverpool?) in 1941.

 

[MattII]

Decisive Battles the Blitzkrieg from Warsaw to Paris includes a Sealion scenario, which you can either play separately or as part of the whole campaign. The sea element is abstracted but even suffering 40% casualties for units just for landing in England and using an as-planned deployment (with delays for the second wave etc) I was able to win as the Germans. You can deploy the German units as you like (within very strict shipping limitations) but I have put a description of how to play the Sealion deployment and plan on their forum.

Hm, interesting. However, computer games also simplify major logistical issues, which lends an unrealism to the game.

 

[sitalkes]

Supply plays an important role in that game, and has some quite clever rules, it's realistic though you may tire of moving so many units around. The German ability to reinforce and supply is progressively reduced throughout the game. Each turn, you get a few shipping points and have to choose which unit(s) you want to cross the channel (usually two infantry divisions or 1 mobile division plus some support troops). You get sufficient shipping points on the first two turns to get nine infantry divisions across (without artillery - none of the first wave units has artillery or armour). The shipping points go down considerably if there is a storm and are also reduced over time. There are about ten different scenarios (including an American intervention) that allow you to make it harder or easier for each side, such as fewer shipping points for the Germans, British troops fighting harder, British troops being sent overseas etc etc. Air attacks are included.

 

[MattII]

How does it deal with unconventional defences such as tiger Moths deploying Paris Green? Also, you say you get 'shipping points', but is that for troops alone, or is it split between troops and supplies?

 

[sitalkes]

There's no Operation Banquet but you can do gas attacks by aircraft. It is a regiment/brigade level game you do get quite a variety of units. You get supply points (measured from units to HQs and up chains of commands) as well as shipping/transport points, they are separate. The game can be modded so hopefully somebody will add in all the extras possible. Anyway it looks pretty grim for the Germans until they get some artillery and mobile divisions landed. The British can also move Home Guard units anywhere on the map. You can see the level of detail and a combat example here: http://www.matrixgames.com/forums/tm.asp?m=2561038 and some initial screens here: http://www.matrixgames.com/forums/tm.asp?m=3594443&mpage=1&key=&#3594445

You can see all the variants here:

 

[Intosh]

The German troops would fall from the barges into the cold waters of the Channel...

The RIVER barges will sunk because they are designed for RIVERS.

3 or 4 years, two rivers barges sunk in the middle of Paris in the Seine from the waves of a Bateau Mouche (long and slow boat for tourists)....

And the Channel is a very heavy sea. I sail on the Channel and the North Sea from 30 years.

 

[MattII]

I've heard they would have a better chance if light-loaded, but then that increases the number of barges you need. Another issue is the length of the barges, the decks of the LCVP were a short 5.26m (total length 11.05m), whereas the barges were mostly either 38.5m or 50m long (albeit with a shorter deck), so unloading would take respectively longer than with the LCVP, meaning more time beached and vulnerable for those unloading troops, and with only about a third of the barges being powered in any case and not all of them having enough power to overcome the channel's strong tides, you want to spend as little time as possible on the beach.

 

[patch_g]

The RIVER barges will sunk because they are designed for RIVERS.

3 or 4 years, two rivers barges sunk in the middle of Paris in the Seine from the waves of a Bateau Mouche (long and slow boat for tourists)....

And the Channel is a very heavy sea. I sail on the Channel and the North Sea from 30 years.

I was just puzzling on a question when I saw your post, so I'll ask:
If 100 of these barges were crossing the Channel and the waves were sea state 3, how many would sink due to the weather conditions?

 

[Ian Hathaway]

I've heard they would have a better chance if light-loaded, but then that increases the number of barges you need...

Ummmmm .... not really. If each man and his kit weighed 150kg (and believe me they wouldn't), and the barges were capable of carrying 150 men that weighs in at 22.5 tonnes on a barge that can take 250-400 tonnes. If anything they may have to add ballast.

If you consider a barge can take 4 or 5 tanks even if each tank was 20 tonnes that is still only 100 tonnes. Basically it was floor space that would limit what could be carried not the weight of what was being carried.

 

[MattII]

Add in the reinforced concrete floor for the tank carriers. Also, this isn't all to the advantage of the barge, since it also means that it gains only a minimal boost after dropping off its load (the LCVP was 2-3 knots faster when empty than when loaded).

 

[Ian Hathaway]

Add in the reinforced concrete floor for the tank carriers.

Lets say they use 150 tonnes of reinforcing or the equivolent of a 1 foot thick layer in the 400 tonne barges that's still only a load of 250 tonnes.

 

[Julius Vogel]

These are the Rhine long barges right?

 

[MattII]

Yep, they're long ones, and thus slow to unload, and not very manoeuvrable.

 

[Ian Hathaway]

These are the Rhine long barges right?

That's correct, yes, the Rhine river barges.