Sealion Naval Forces

[Glenn239]

"This operation is being planned as a success, We can not afford to fail."
General Dwight D. Eisenhower.

A repulse of D-Day would have been a serious tactical reversal but,

http://en.wikipedia.org/wiki/Operation_Dragoon

probably would not have kept the Allies from liberating France in 1944, even if no second invasion was attempted in the north until after Dragoon had secured southern France.

What I find particularly amusing about this thread is that you are as blind to reason, as impervious to reality...<snip>

More hyperbole does not transform a brigade level defence to a divisional strength defense on IOW. Show me 2 divisions on IOW, and I'll show you an island that was immune to attack, (Malta had about 30,000 troops (4 brigades with armor support) for an island less than half the size with more fortification).

Doesn't take too much to go wrong before an assault on IOW to fail. Logistically, not only was transport a problem, but after the French campaign the Germans must have been short on assault gliders. Finding enough parachutes would also have been a large hurdle - I see that purchasing teams were all over Europe looking for parachutes.

and as convinced of your own genius in the face of everybody else's stupidity as Ovaron himself

I find the position taken by posters attacking any suggestion of German offensive air-sea operations in 1940 in the Channel to be dogmatic, but I don't find it to be stupid. Common sense indicates that any such action would be very risky tactically against the RN and RAF. But strategically - the risk was worth it, even given the poor tactical conditions.

 

[sharlin]

Stirring the pot time again Glenn? Predictable...verrrry predictable.

 

[oldironside]

What's the first rule? Don't take the bait.

 

[Mike D]

Stirring the pot time again Glenn? Predictable...verrrry predictable.

I liked the bit about Malta being half the size of the IoW. That either makes the IoW roughly the size of Dominica or Malta slightly smaller than a regulation snooker table.

 

[sharlin]

I liked the bit about Malta being half the size of the IoW. That either makes the IoW roughly the size of Dominica or Malta slightly smaller than a regulation snooker table.

As I said its predictable. Silent for a while....*REALLY SILLY POST THAT STATES FALSEHOODS AND WEHRABOONESS IN DENIAL OF REALITY*....*watches people bicker with a trollface*

Its what he does.

 

[Scotty]

The German special forces overall seemed pretty lacklustre in WW2.

But these are the special forces in snazzy uniforms that you'll have on the IOW having tea and crumpets before lunchtime in your fantasy world though....

 

[Ian Hathaway]

Getting back to the topic of the thread for a few moments ...

I have finally finished working on the list of RN vessels available to repel the initial invasion wave based on a date of 24th September 1940. In total I've identified the locations of over 1300 vessels in home waters, from Battleships to Lighters with another 300 or so with an unknown location (these are smaller boats only, the major units are reasonably easy to find). I have then calculated which of these is within 15 hours of the invasion area based on 75% speed and assuming that all are on high alert, i.e. 30 minutes notice to sail.

The ships include:

• Battleship Revenge
• Monitor Erebus (15" Guns)
• Light Cruisers Emerald, Aurora, Curacoa, Manchester and Newcastle.
• Destroyers Campbell, Mackay, Malcolm, Scimitar, Vanity, Verdun, Vimiera, Wolsey, Vanoc, Vesper, Viscount, Venetia, Beagle, Brilliant, Bulldog, Garland, Blyskwica, Icarus, Impulsive, Intrepid, Jackal, Jupiter, Kashmir, Kelvin, Kipling, Vansittart, Venomous, Verity, Volunteer, Whitehall, Veteran, Wild Swan, Witherington, Wivern, Wolverine, Worcester, Broke, Ashanti, Bedouin, Cossack, Eskimo, Maori, Matabele, Sikh, Somali, Tartar, Zuluand Burza.
• Escort Destroyers Berkley, Cattistock, Fernie, Garth, Hambledon and Holderness.
• Plus 20 MTBs, 2 Sloops, 8 Corvettes, 8 Fleet Minesweepers, a Gunboat, 8 Large Patrol Vessels, 159 Trawlers (ASW and MS Trawlers) and 258 other boats of limited use.

The key moments of the Channel clashes would happen at 2-3 hours when the major forces from Sheerness and Harwich arrive with 2 Cruisers and 19 Destroyers enter the fray with the MTBs from Harwich and Portsmouth also arriving. At 5-6 hours the 6 Destroyers out on Operation GL would arrive in conjunction with the Monitor Erebus.

 

[Saphroneth]

Right, that's good to know.

Not to repeat myself, but - with that lot, it seems like the only feasible invasion of Great Britain is one that takes a single morning...

 

[Ian Hathaway]

Right, that's good to know.

Not to repeat myself, but - with that lot, it seems like the only feasible invasion of Great Britain is one that takes a single morning...

In itself I'm not sure this is enough to prevent the first wave getting through ... BUT ... and it's a huge BUT ... I think this proves what everyone has already been saying, it's not about preventing the first waves, it's about preventing the resupply and reinforcement. 500 or so RN vessels might be available on the first day ... and even if they are all sunk that still leaves 800 more to do the real damage and that includes most of the heavies.

 

[Saphroneth]

In itself I'm not sure this is enough to prevent the first wave getting through ... BUT ... and it's a huge BUT ... I think this proves what everyone has already been saying, it's not about preventing the first waves, it's about preventing the resupply and reinforcement. 500 or so RN vessels might be available on the first day ... and even if they are all sunk that still leaves 800 more to do the real damage and that includes most of the heavies.

Exactly - if they can pull off the whole invasion with what they can land on the morning of day one, then sure, it would work. And it's why it works in Hearts of Iron or the like.
But in the real world you can't do that. It hasn't been an option since... what, the late nineteenth century at the latest? (Probably since about ten minutes after the invention of all-in-one cartridges, because before then all you really needed was gunpowder and lead and you could theoretically make ammunition.)

 

[larpsidekick]

In itself I'm not sure this is enough to prevent the first wave getting through ... BUT ... and it's a huge BUT ... I think this proves what everyone has already been saying, it's not about preventing the first waves, it's about preventing the resupply and reinforcement. 500 or so RN vessels might be available on the first day ... and even if they are all sunk that still leaves 800 more to do the real damage and that includes most of the heavies.

Ian, thanks for that analysis. I think your reading of the evidence is correct, and widely accepted - an initial landing is not beyond the realms of possibility, a successful Sealion is.

 

[Glenn239]

But these are the special forces in snazzy uniforms that you'll have on the IOW having tea and crumpets before lunchtime in your fantasy world though....

The FJ formations described in Seewelpe would have had to be more than half regular infantry pressed into airborne service, with all the disadvantages inherent to that. The paratroop forces after the Battle of France appear insufficient (in and of themselves) for an operation half this size.

 

[Glenn239]

I liked the bit about Malta being half the size of the IoW. That either makes the IoW roughly the size of Dominica or Malta slightly smaller than a regulation snooker table.

You are right - looks about 147 square miles with 1 brigade to about 95 square miles with 4 brigades on Malta Island, (I assume the bulk of the defences for Malta were on this island?)

 

[Glenn239]

The ships include:

• Battleship Revenge
• Monitor Erebus (15" Guns)
• Light Cruisers Emerald, Aurora, Curacoa, Manchester and Newcastle.
• Destroyers Campbell, Mackay, Malcolm, Scimitar, Vanity, Verdun, Vimiera, Wolsey, Vanoc, Vesper, Viscount, Venetia, Beagle, Brilliant, Bulldog, Garland, Blyskwica, Icarus, Impulsive, Intrepid, Jackal, Jupiter, Kashmir, Kelvin, Kipling, Vansittart, Venomous, Verity, Volunteer, Whitehall, Veteran, Wild Swan, Witherington, Wivern, Wolverine, Worcester, Broke, Ashanti, Bedouin, Cossack, Eskimo, Maori, Matabele, Sikh, Somali, Tartar, Zuluand Burza.
• Escort Destroyers Berkley, Cattistock, Fernie, Garth, Hambledon and Holderness.
• Plus 20 MTBs, 2 Sloops, 8 Corvettes, 8 Fleet Minesweepers, a Gunboat, 8 Large Patrol Vessels, 159 Trawlers (ASW and MS Trawlers) and 258 other boats of limited use.

The key moments of the Channel clashes would happen at 2-3 hours when the major forces from Sheerness and Harwich arrive with 2 Cruisers and 19 Destroyers enter the fray with the MTBs from Harwich and Portsmouth also arriving. At 5-6 hours the 6 Destroyers out on Operation GL would arrive in conjunction with the Monitor Erebus.

What is your estimated position in the Channel for when the force of 2xCL / 19D intercepts - closer to the French shore, or the Dover shore?

 

[Glenn239]

In itself I'm not sure this is enough to prevent the first wave getting through ... BUT ... and it's a huge BUT ... I think this proves what everyone has already been saying, it's not about preventing the first waves, it's about preventing the resupply and reinforcement.

The RN objective was about both - disrupting the cohesion of the initial landing so that the British Army could effectively counterattack the beachheads against an opposition as dispersed and disorganised as possible, as well as disrupting the movement of follow up waves and supply.

 

[Glenn239]

Exactly - if they can pull off the whole invasion with what they can land on the morning of day one, then sure, it would work.

A one-morning landing could only be made at a fraction of the strength of Sealion, meaning that it either must attack a target isolated from the bulk of British army reserves such as IOW, or it must be Garrison's raiding force which must plan to depart before British army reserves, or major RN formations, arrive in force.

 

[Saphroneth]

A one-morning landing could only be made at a fraction of the strength of Sealion, meaning that it either must attack a target isolated from the bulk of British army reserves such as IOW, or it must be Garrison's raiding force which must plan to depart before British army reserves, or major RN formations, arrive in force.

You know what?

For the sake of argument, let's assume that the Germans manage to land troops on the Isle of Wight.

What stops the Brits from retaking it again?

 

[Torqumada]

What stops the Brits from retaking it again?

Isn't it obvious? Their surrender in the face of Nazi audacity.

Torqumada

 

[Ian Hathaway]

Getting back to the topic of the thread for a few moments ...

I have finally finished working on the list of RN vessels available to repel the initial invasion wave based on a date of 24th September 1940. In total I've identified the locations of over 1300 vessels in home waters, from Battleships to Lighters with another 300 or so with an unknown location (these are smaller boats only, the major units are reasonably easy to find). I have then calculated which of these is within 15 hours of the invasion area based on 75% speed and assuming that all are on high alert, i.e. 30 minutes notice to sail.

The ships include:

• Battleship Revenge
• Monitor Erebus (15" Guns)
• Light Cruisers Emerald, Aurora, Curacoa, Manchester and Newcastle.
• Destroyers Campbell, Mackay, Malcolm, Scimitar, Vanity, Verdun, Vimiera, Wolsey, Vanoc, Vesper, Viscount, Venetia, Beagle, Brilliant, Bulldog, Garland, Blyskwica, Icarus, Impulsive, Intrepid, Jackal, Jupiter, Kashmir, Kelvin, Kipling, Vansittart, Venomous, Verity, Volunteer, Whitehall, Veteran, Wild Swan, Witherington, Wivern, Wolverine, Worcester, Broke, Ashanti, Bedouin, Cossack, Eskimo, Maori, Matabele, Sikh, Somali, Tartar, Zuluand Burza.
• Escort Destroyers Berkley, Cattistock, Fernie, Garth, Hambledon and Holderness.
• Plus 20 MTBs, 2 Sloops, 8 Corvettes, 8 Fleet Minesweepers, a Gunboat, 8 Large Patrol Vessels, 159 Trawlers (ASW and MS Trawlers) and 258 other boats of limited use.

The key moments of the Channel clashes would happen at 2-3 hours when the major forces from Sheerness and Harwich arrive with 2 Cruisers and 19 Destroyers enter the fray with the MTBs from Harwich and Portsmouth also arriving. At 5-6 hours the 6 Destroyers out on Operation GL would arrive in conjunction with the Monitor Erebus.

Following on from this, a simplistic analysis of the "Battle of the Channel" would give us an idea of the losses sustained by both sides and of what forces the Germans could land on British soil.

I have looked at the relative strengths of each ship/boat involved based on a very simple formula of firepower alone taking into consideration the weight of shot, range and rate of fire of the weaponry of the vessels of both sides. This gives the following results as a comparison to the British Tribal Class Destroyer:

• German Destroyers are 13% stronger than the Tribal Class. Their guns (12.7cm as opposed to the 4.7" QF of the Tribal) fire a heavier projectile over a greater distance and at a quicker rate.
• In comparison a British Light Cruiser is typically 3 times better than a Tribal.
• The Battleship HMS Revenge has the Equivolent firepower of 15+ Tribals.
• In contrast the British V & W destroyers (the most numerous) are only rated at 1/3 the strength of the Tribal.
• On the German side the 1935 Class Torpedo Boat is slightly weaker than the V & W destroyer however the Raubtier Class Torpedo Boats which also carry the 12.7cm gun are twice as good as the V & W.
• It would take 11 or 12 ASW Trawlers to pack the same punch as a Tribal.

I know that is pretty basic but it will hopefully give a good idea of what might happen.

The following assumptions have been made, but these assumptions can be changed and the analysis run again:

• The British have received copies of the plans showing landing beaches and convoy routes, but not dates and times. The plans were only confirmed as genuine at the last minute however so the RN was not able to redeploy shipping but does know where to target their attacks. Basically their is no delay due to fog of war or uncertainty of the exact location of the invasion area.
• The British identify the German buildup and place all units on alert to sail at 30 minutes notice. This again means that there are no delays in interception.
• Due to the above the British use their network of Dutch, Belgian and French informants to tell them of the exact moment of departure of the invasion convoys and can set sail and intercept as quickly as possible.
• On receipt of orders all ships and small boats depart from their respective locations from Plymouth, along the South Coast and up the East Coast as far as Rosyth (all other locations are out of range). To avoid overstressing the ships all sail at 75% max speed. No breakdowns or collisions occur.
• Mines can be ignored as the British know where they are going and they have been constantly keeping cleared lanes.
• The German convoys begin moving at 22:00 on 23rd September utilising the darkness to best advantage. The convoys finish forming up off the English coast at 08:00 on the 24th and begin their run to the beaches at this time. The first troops land at 09:00 and continue until all are landed or the remaining transports/barges are sunk.
• Half light is between 06:00 and 7:00 with full light at 07:00 onwards.
• From first sailing to the German ships returning to port takes 16 hours (the slower barges are abandoned on the beaches to be recovered at a later date.)
• No air attacks have been taken into account. It is assumed that the Luftwaffe either fails to break through the fighter screen or is occupied elsewhere. The same applies to the RAF.
• As per Admiralty orders the RN is tasked with targetting the transports and only engaging with war ships if directly threatened. As such 80% of damage has been allocated to the German transports and 20% to German warships.
• To try to balance the argument that the German sailors were not as good as those of the RN and that their ships were poorly designed the rating of their ships has been reduced by 1/2 in all calculations.

I will post the results shortly ...

 

[sharlin]

Ian don't try and break this down into mathmatical formulae.

Yes the German guns fired a heavier shell, but they also fired them with a slower rate of fire. A weaker RN vessel could (and indeed DID) defeat them with their higher rate of fire. A formulae won't take into account that the big german DDs were lousy gun platforms for their large guns, making them not as accurate as an equivalent RN ship (the Germans did not design a good destroyer really).

Looking at the numbers and going purely off them won't work.