Seelöwe: British Defensive Measures - Tanks, Flak, Artillery

[RichTO90]

I have edited the thread title to more accurately reflect the discussion going on here and to avoid having to split out another thread. - Andreas

Okay, I guess I'll be the 800-pound gorilla and kick this off.

Were the British as helpless in the face of a Seelöwe assault? In other words, let's assume that the assault convoys went off as planned 27 September when it appears the main concentration had been completed. So it is late Friday evening 27 September 1940 and the Seelöwe expedition 'gegen England' has set off, exactly as laid out.

What do the British have to stop it with? And how effective will the defense be? I'll start off.

AA Command Dispositions as of 16 September 1940:
4th AA Division (HQ Chester, area Liverpool-Manchester-Birmingham, supporting 12 and 13 Groups, FC)
– 186 HAA, 84 LAA, 397 AAMG
5th AA Division (HQ Reading, area Falmouth-Plymouth-Portsmouth, supporting 10 and 11 Groups, FC)
– 293 HAA, 190 LAA, 553 AAMG
6th AA Division (HQ Uxbridge, area Dover-Medway-Harwich, supporting 11 Group, FC)
– 185 HAA, 141 LAA, 397 HAA
1st AA Division (HQ Kensington, area London, supporting 11 Group, FC)
– 235 HAA, 44 LAA, 161 AAMG
2nd AA Division (HQ Watnall, area Norwich-Sheffield-The Humber, supporting 12 Group, FC)
– 131 HAA, 82 LAA, 835 AAMG
7th AA Division (HQ Newcastle, area Leeds-Tyne-Tees, supporting 13 Group, FC)
– 114 HAA, 55 LAA, 277 AAMG
3rd AA Division (HQ Edinburgh, area Northern Ireland and Scotland, supporting 13 Group, FC)
– 179 HAA, 132 LAA, 367 AAMG
Total – 1,323 HAA, 728 LAA, 2,987 AAMG

The most important of course are the 1st, 5th and 6th Divisions. 6th Division in particular from the information I have been able to glean, was fairly well situated for a dual-purpose role. The light AA - 40mm Bofors, which were the most critical equipment shortage at this time and the AAMG (mostly Vickers and Lewis) - were mostly concentrated around the airfields. The heavy AA - 3.7-inch with a smattering of 4.5-inch and even a few 5.5-inch - were more heavily concentrated towards the Kentish coastline and along the estuary of the Thames. For example, there were 72 guns concentrated along the southern shore of the Medway and Thames and 48 along the northern shore. Another 14 were around Dover and 8 at Harwich. The other 43 were at the 8 airbases in Kent, typically in four or eight-gun batteries (although I can give more details if anyone is interested).

So what next?

[RichTO90]

Er, uh, no reply?

Okay, how about coastal batteries?

This is what I have for Dover so far:

Citadel Battery - three Mk X 9.2-inch guns
Royal Marine Battery – three 13.5 Mk V railway guns (Gladiator, Bruce, and Scene Shifter) and one 18-inch railway howitzer (Boche Buster)
Wanstone Battery (Fan Bay) – (emplaced in open mounts; enclosed battery completed in Sep 42)
three MK XV 6-inch guns
two Mk I 15-inch guns (Jane and Clem)
(four Mk XV 6-inch were added in 1942)
Pier Extension Battery – two 12-pdr 20 cwt guns
St Martins Battery – three Mk VII 6-inch guns
Pier Turret Battery – two Mk VII 6-inch guns
Lydden Spout Battery – two 6-inch guns
Burgoyne Battery – four 18/25-pounders
Capel Battery – three Mk VIII 8-inch
Other Dover guns
1 14-inch gun (Winnie, arrived early July and was operational 7 Aug 40, Pooh followed in Feb 41)

Uh essentially, unless the two Pier batteries are seized by a coup any vessels entering Dover Harbor are quickly going to be turned into charnel houses - the 12-pounder 20 cwt guns were highly accurate and capable of a high rate of fire, the 6-inch Mark VII guns were considered to be one of the best of their day and were in service from about 1910 to 1956.

Overall, it looks like by about September 1940 there were something like two coast artillery guns per kilometer of beach between Dover and Bognar Regis. That could be compared to Omaha Beach's 7 to 9 kilometers of frontage where there was....none?

[Gooner1]

Total – 1,323 HAA, 728 LAA, 2,987 AAMG

I have slightly different totals taken from 'AA Command' by Colin Dobson.

As of 18th September 1940
HAA
4.5" - 374
3.7" (static) - 408
3.7" (mobile) - 355
3.0" (with predictor) - 225
Total 1362

LAA
3.0" (without predictor) - 116
Bofors - 474
2pdr (Single/Twin) - 102
2pdr Naval - 49
Hispano 20mm - 61
Total 802

A report by 6th Anti-Aircraft Division entitled "Some Problems and Achievements of Anti-Aircraft Gunnery during the Battle of Britain" and dated 2nd August 1941 stated on ground defence that -
'Preparations were made by all A.A. defences to assume a secondary ground-defence role; Bofors were provided with anti-tank ammunition and sited to cover approaches to aerodromes, V.P.'s [Vulnerable Points] etc. Certain 3.7-inch guns suitably sited were given an anti-ship role, and preparations were made for barrages to be put on certain beaches. Under the immediate threat of invasion in May 1940, mobile columns of A.A. troops were formed, but these troops reverted to their A.A. role before the Battle of Britain began.'

[Gooner1]

Coastal artillery in 45th Division area - from Dymchurch excluding the Redoubt to Telscombe Cliffs just west of Newhaven - as of 15th October 1940, were:

3 - 9.2" guns (on railway mountings).
19 - 6" guns "
4 - 4.7" guns. "
2 - 4" guns. "
2 - 12 pdrs.

In addition thirteen 4" Naval Guns (four static and nine mounted on armoured trucks) were distributed along the coast in support of 45th Div.


Dymchurch Redoubt contained another three or four 6" guns.

[RichTO90]

I have slightly different totals taken from 'AA Command' by Colin Dobson.

As of 18th September 1940

Hi gooner!

Different days? I just noticed that I misstyped the date, it was actually as of 11 September. My figures are taken from those recorded for four different periods (11 July, 21 August, 11 September, and 9 October) in Appendix 35 to the RAF History of the Battle of Britain (Air 41/16). It doesn't have the breakdown by type of individual pieces, but it does have the distribution by number of guns by area, which is interesting.

[RichTO90]

Coastal artillery in 45th Division area - from Dymchurch excluding the Redoubt to Telscombe Cliffs just west of Newhaven - as of 15th October 1940, were:

3 - 9.2" guns (on railway mountings).
19 - 6" guns "
4 - 4.7" guns. "
2 - 4" guns. "
2 - 12 pdrs.

In addition thirteen 4" Naval Guns (four static and nine mounted on armoured trucks) were distributed along the coast in support of 45th Div.


Dymchurch Redoubt contained another three or four 6" guns.

These are the batteries I have found so far. Some of them may be later installations though, I'm still trying to find out when they were operational. But most of the emergency 4.7 and 6-inch batteries were installed very quickly and were operational by August at the latest. From 1 July to 31 December 1940 a total of 153 new coastal batteries were emplaced in England as part of the emergency battery program, totaling over 600 pieces, many of them ex-RN 9.2-inch, 6-inch, and 4.7-inch pieces mounted as two or four-gun batteries. By mid summer 1940 a total of 40 emergency batteries had been completed at Falmouth, Plymouth, Portland, Portsmouth, Newhaven, and Dover. By 4 June a total of 50,000 AT mines had been issued and another 200,000 more ordered for the beaches Fraserburgh-Southampton.

Folkestone
East Battery – two 6-inch
West Battery – two 6-inch
Copt Point Battery – two Mk II 6-inch

Hythe
Ardhallow Battery – two 6-inch

Dymchurch
Tower Battery – four Mk II 6-inch
Redoubt Battery – four Mk XII 6-inch

Dungeness
East Battery – three Mk VII 6-inch
West Battery – two Mk V 4.7-inch

Hastings
Hastings Battery – two Mk XIII 4-inch

Bexhill-on-Sea Battery – two Mk XIII 4-inch

Eastbourne
Cooden Battery – one 5.5-inch
Emergency Battery – two 6-inch
Langley Redoubt – one 12-pounder
Wish Tower – two Mk II 6-inch

Brighton Battery – two Mk II 6-inch

Beachy Head
Cuckmere Haven Battery – four 6-pounder (Hotchkiss)

Seaford Battery – two 6-inch

Newhaven
Newhaven Fort – two 4-inch and two 12-pounder 20 cwt

6-inch - 27
5.5-inch - 1
4.7-inch - 2
4-inch - 6
12-pounder - 3
6-pounder - 4

[Gooner1]

Hi Rich!

The figures I posted were taken from the Divisional Defence Scheme of 45th Division dated 15th October 1940 found in WO 166/536.

The distribution of their artillery was -


"A" Sub-area

(a) Under Comd.
55. Fd. Regt.
14 - 75's (two sited for A/Tk.)
6 4.5" how.
4 - 25pdr.
275 A/Tk. Bty. 8 - 2pdrs.

(b) In support.
(under comd C.R.A.)
Elements X Defence Regt. 5 - 4" guns.

Elements 3/56 & C/56 Hy. Regt.
(2 - 6" guns
(1 - 9.2" how.

(c) Covering the the front.
(under comd C.C.M.A.)
3 - 9.2" guns, railway mountings.
8 - 6" guns. C.D.
2 - 4.7" guns C.D.

"B" Sub-area

(a) Under comd.
142 Fd. Regt.
10 - 75 m.m. (two sited for A/Tk)
8 - 4.5" how.
274 A/Tk. Bty. 4 - 2 pdrs. (274 Bty. has 4 - 2pdrs in Div. Reserve.)

(b) In support.
(under comd C.R.A.)
Elements X Defence Regt. 5 - 4" guns.
Elements 3/56 , C/56 and D/56 Hy. Regt.
2 - 6" guns
3 - 9.2" How.

(c) Covering the the front.
(under comd C.C.M.A.)
2 - 4" C.D.
2 - 4.7" C.D.
5 - 6" C.D.

"C" Sub-area.

(a) Under Comd.
96 Fd. Regt.
12 - 75 m.m. guns
6 - 4.5" hows.
4 - 25 pdrs.
2 - 6 pdrs. (sited for A/Tk).
276 A/Tk. Bty. 8 - 2 pdrs

(b) In support.
(under comd C.R.A.)
Elements X Defence Regt. 3 - 4" guns
Elements A/56, D/56 Hy. Regt. 2 - 6" guns
2 - 9.2" hows.
2 - 8" hows.

(c) Covering the the front.
(under comd C.C.M.A.)
2 - 12 pdrs. C.D.
6 - 6" guns. C.D.

(Noted :- 4 - 6 pdrs at Trg. Centre, EASTBOURNE.)


The Brigade Sub-areas were
'A' Sub-area - Dymchurch (excl. Redoubt) to excl. Camber.
'B' Sub-area - Camber to excl. Pevensey.
'C' Sub-area - Pevensey to Telscombe.

[RichTO90]

Hi Rich!

The figures I posted were taken from the Divisional Defence Scheme of 45th Division dated 15th October 1940 found in WO 166/536.

The distribution of their artillery was - (snip)

Excellent! Part of the problem with the battery listings is that they are complete, but as I said it's impossible to tell when they became active. I think this is more accurate and we can probably place the named batteries within the context of the 45 Division organization.

It also answers a number of questions.

1). The divisions holding the coast were pretty well organized and equipped for the defense of the coastline by late summer.
2). 2-pounder AT and 25-pounder field were still in somewhat short supply.
3). AT defense and artillery were already well supplemented by the arrival of US 75mm guns.

About the only thing not good is the nearly 80 linera kilometer front of the division. On the other hand, large portions of the coast aren't accessible to landing IIRC so I expect the division defense areas was concentrated on the proposed German landing sites? It seems obvious that the other divisions of XII Corps would have been similar and considering that 1 London Division was a first line Territoreal Division it may have actually been better equipped. I show:

Southeastern Command – Kentish coast from the Thames to Portsmouth
HQ XII Corps (Southern Approaches to London, Portsmouth to Ramsgate)
1 (London) Division (1st Line Terr.) - Dymchurch
45 (Wessex) Division (2nd Line Terr.)
New Zealand Division (-) (reserve)
5 Brigade – E of Maidstone, C/A on line Dover-Folkestone
21 Bn – SE of Maidstone
22 Bn – Hollingbourne and Warren Wood
23 Bn – (Bren and Boys issued June, at WE by mid-August)
7 Brigade – N of the Maidstone-Charing Road,
Mission: To counter-attack vigorously any enemy landing in London
Division area (Sheerness-Dymechurch redoubt) especially in the area
north and north-west of Dover and Folkestone. To re-establish the line of the Royal Military Canal eastwards of Main
Street..
Concurrently with the above, to deal with any hostile airborne landings
in the area Sittingbourne-Faversham-Charing-Maidstone.
28 (Maori) Bn – Doddington
Composite (29) Bn
4 AT Company
Milforce
8 RTR – Charing (from 1 Army Tank Brigade, probably 52 Infantry Tank Mk II and 7 Light Tank Mk VI)
C Squadron, NZ Division Cavalry – Westwell (probably about 14-20 Lt Mk VI and Carriers)
Medium MG Company
5th NZ Field Regiment
E and F Battery – 8 75mm (ex-US M1897) each
G Battery – 8 25-pdr Mk II
7th NZ AT Regiment (received new 2-pdr in August)
31st Battery - 8 2-pounder
32nd Battery - 8 2-pounder
1 Motor MG Brigade
16/5 Lancers
17/21 Lancers
2 Lothians and Border Horse Yeomanry

Note that the proposed landing by Meindl's Luftlande Sturm Regiment (really a strongly reinforced battalion at this time) at Hythe and the airfield at Lympne would probably be met by elements of 1st London Division and then would be counterattacked by 7th New Zealand Brigade and Milforce.

Anyway, thanks for the details, more grist for the mill.

[Gooner1]

About the only thing not good is the nearly 80 linera kilometer front of the division. On the other hand, large portions of the coast aren't accessible to landing IIRC so I expect the division defense areas was concentrated on the proposed German landing sites? It seems obvious that the other divisions of XII Corps would have been similar and considering that 1 London Division was a first line Territoreal Division it may have actually been better equipped.

Yes, it is a long frontage but as you say quite a bit of it is inaccessible (Beachy Head!) but 45th Division did have quite a few attached troops. From the Defence Scheme:

31 Inf. Bde Gp ( being relieved by 198 Ind. Inf. Bde)
219 Inf. Bde.
56 Hy Regt R.A.
One Home Defence Regt. R.A. (Recently reformed - under training)
1 C.W. Gp. R.E. (probably moving shortly)
18. R. Fus. (Pnr Bn) (placed under comd "A" Sub-area)
7 Devons (M.G. Bn)
Dets 2/8 Bn. R. Sussex (H.D. Bn.) (only under comd 45 Div. operationally)
6 "Commando" (placed under "A" Sub-area - moving shortly)
3 Independent Coy (ditto)
13 Motor Coach Coy.
Certain administrative units.

31st Infantry Brigade Group was tasked to hold the Royal Military Canal and moved into position from 25th September, their artillery comprising 75 Fd. Regt. of 24 - 25 pdrs and 223 A/Tk Bty. of 12 - 2 pdrs.
The Commando and Independent Company were specifically assigned the defence of the coastal batteries.

[RichTO90]

219 Inf. Bde.

Thanks for the addtional detail, but I think 219 Brigade would have been out of it since they were formed in late October? Fundamentally, the German timeframe was restricted by the KM requirement for at least a half-moon for maneuvering visibility, which limits the days to:

Full Moon – 16 September to Third Quarter Moon – 24 September
New Moon – 1 October to Waxing Crescent Moon – 3 October
First Quarter Moon – 8 October to Full Moon – 16 October (note that from that point the operation was effectively postponed until spring 1941)

Now, the weather was uncooperative from 9 September to the evening of the 21st when it improved. Channel conditions were such that the S-Boot operations were essentially halted for this period and it is unlikely then that an assault convoy could have sailed. So that leaves:

21st September 1940
Weather: Mainly fine. Operations by German S-Boot resume for the first time since 9 September due to weather conditions.
possible
22nd September 1940
Weather: Dull with fog in the morning. Cloud clearing during the afternoon. Some rain.
not possible
23rd September 1940
Weather: Fine
possible
24th September 1940
Weather: Early morning fog in northern France. Channel cloudy with haze in the Straits and Thames Estuary.
not possible

So single day 'windows' not really conducive to sustained operations.

1st October 1940
Weather: Mainly fair, but generally cloudy.
possible
2nd October 1940
Weather: Blue skies during the day with cloud building up later
possible
3rd October 1940
Weather: Rain and drizzle in the Channel. Visibility down to 500 yards in places.
not possible
4th October 1940
Weather: Mist, rain and poor visibility throughout the day. Fog at night.
not possible

So a two day 'window' followed by two days of bad weather.

8th October 1940
Weather: Cloudy in the south-east but fair. High winds.
possible
9th October 1940
Weather: Cloudy in the Channel with rain in northern France and the Straits of Dover.
not possible
10th October 1940
Weather: Showery with bright intervals. Haze in the Thames Estuary and East Anglia.
possible?
11th October 1940
Weather: Mainly fair apart from showers in coastal areas. Fog developed during the night.
not possible
12th October 1940
Weather: Widespread mist and fog during the day, clearing later.
possible
13th October 1940
Weather: Early fog clearing to blue skies. Cloud later.
not possible
14th October 1940
Weather: Occasional rain or drizzle spreading to the south-east.
not possible
15th October 1940
Weather: Fair but cloudy in the Straits. Clear, moonlit night.
possible
16th October 1940
Fog widespread in Germany and France. Wet and misty night.
not possible

[LWD]

If it has to be at least a half moon shoudn't the allowable time increments be 2 week periods ie from waxing half moon ot waning half moon? If they were going for the max or min tidal differential then this would addtionally restrict the intervals.

[RichTO90]

If it has to be at least a half moon shoudn't the allowable time increments be 2 week periods ie from waxing half moon ot waning half moon? If they were going for the max or min tidal differential then this would addtionally restrict the intervals.

Not according to the lunation calender I looked at....but most of it was Greek to me so I'll gladly accept corrections. And they hadn't really considered tides too much that I can find, the only other requirement was that the Heer wanted to land at dawn. Of course since the glider assault was to go in a half hour prior to the sea landing that complicates things as well. And of course the weather simply wasn't very cooperative....fog and rain at night was a no-no since all the station keeping for the thousands of unwieldy barges was visual. And a morning fog or rain would be problematic as well. Worse, there was every likelihood that the French airfields might be socked in while British bases were not and vice versa and given the problematic German weather prediction capabilities....

[LWD]

From the waxing half moon through full to the waning half moon will be ~14 days followed by 14 days with less than half moon (wanning half through new to waxing half). Tides were one of the serious problems the Marines ran into at Tarawa. If they land at low tide then the rising tide might casue some problems with unloading as it will tend to refloat the barges. If they land at high tide the barges won't get off until the next high tide if at all. Landing after high tide might be best as it gives them several hours before refloating becomes a problem (an hour after high tide would give them about 10 hours) but still allow for the barges to back off the beach at that time. At full moons you get the largest tides but the highs occur around noon and midnight. Half moons give the smallest tides with the highs occuring around 6PM and AM.

[Gooner1]

Super Heavy Artillery on railway mountings under command 12 Corps September 1940.
(Excluding three 13.5" railway guns of the Royal Marines Siege Regiment)

Two 12" Hows - Shepherds Well.
Two 12" Hows - Eythorne.
Two 12" Hows - Lyminge.

One 9.2" Gun - Bridge (Canadians)
Two 9.2" Guns - Hythe and Folkestone
Two 9.2" Guns - Littlestone (Canadians)
One 9.2" Gun - Golden Wood (Canadians)

Two 12" Howitzers sited on the Canterbury - Ramsgate railway would become operational about 29th September, a further two 12" Howitzers on the Ashford - Hythe Railway about 15th October whilst two 9.2" guns just awaited manning.

[RichTO90]

Super Heavy Artillery on railway mountings under command 12 Corps September 1940.

Very interesting. Overall it appears that although not up to full War Establishment, most of the units, especially thosein the east, southeast and south were pretty strong. From what I've found so far you can conclude that for example, 548 Cruiser Tanks had been built by 30 September; 134 had been lost in France and 137 were in Egypt, which still left over 200 in Britain, enough to equip the four Cruiser regiments of 1st Armoured Division that were active. The situation with Infantry Tanks was even brighter, of 524 completed, 100 were lost in France and 52 had been shipped to Egypt on 18 August leaving well over 350 available, enough to equip the five regiments of the GHQ Reserve 1st and 21st Army Tank Brigade to full War Establishment and leave enough left over to allow the continued training and equipping of the six regiments of 23rd and 24th Army Tank Brigades (essentially a full regiments worth per brigade). And there were a plethora of Light Tanks available, of 1,340 built, 321 had been lost in France and 275 were in Egypt, leaving over 700, more than enough in theory to equip the dozen or so regiments formed to War Establishment. Note that by actual count the three ‘light’ regiments of 22nd Armoured Brigade averaged 42.33 tanks each, 73 percent of their War Establishment of 58.

In terms of newly produced artillery, not counting guns evacuated from France (a total of 322 of all types or roughly one-in-eight had been brought back), there were about 140 2-pdr AT guns, 568 40mm Bofors AA guns, 294 25-pdr guns, 728 3.7-inch AA, and 118 other miscellaneous guns added to the Army from 1 April to 30 September. In terms of ‘B’ Echelon vehicles, 63,879 had been lost in France, but 54,057 new ones had been produced.

Also by that time the initial shipments of equipment sold to Britain by the US had arrived, including 895 M1917 and M1897 75mm guns (enough to temporarily replace all the field guns lost in France and to give the field artillery a strong antitank capability as well), each with 1,200 rounds of ammunition, 300 3-inch mortars, each with 325 rounds of ammunition, 1,157 Lewis MG, 7,071 Vickers MG, 10,000 M1917 MG, and 25,000 BAR.