LWD wrote:The German plan is obviously very dependent on mine sweepers and layers.
Yep.
And the story, as best I cn make out, is:
The Mine Barrier (Minesperren) Plan
West Group –
From Cherbourg: Tannenberg (383-480 mines), Cobra, Togo (225 mines?), Schwerin (converted liner, probably carried a load similar to Tannenberg) , and Schiff 23 (later known as Stier, an auxiliary cruiser)
From Le Havre: Stralsund (World War I reparation to France, re-commissioned by the KM, 120 mines) and Skaggerak (?)
Total capacity was probably about 1,200 mines. They were responsible for laying 8 barriers of various lengths, two off Plymouth, two of Portsmouth, and 4 off Brighton.
East Group –
From Ostende: Grille (120-228 mines), Roland (converted liner, probably carried a load similar to Tannenberg), Preußen (a pre-World War I Baltic ferry and auxiliary minelayer, 400 mines), and Königin Luise (sunk in World War I she was raised and rebuilt, 200 mines)
From Antwerp: Hansestadt Danzig (converted liner, probably carried a load similar to Tannenberg), Kaiser (World War I auxiliary minelayer, 180 mines), and Brummer (280 mines)
Total capacity was probably about 1,900 mines. They were responsible for laying 18 barriers of various lengths off Dover.
Evaluation of the Mine Barrier Plan by Jürgen Rohwer in “Chronik des Seekriegs”:
“The effect of this loss [of two British destroyers in a minefield on 31 August, a third was damaged] on the British side was hardly to be underestimated. However not just in terms of demoralization. The British units also had orders to place mines in order to disturb the approach of the invasion fleet. It may be assumed that with the beginning of Seelöwe operations the landing area would have been mined within the shortest time by English side, and that German mine search and clearing units would have been as helpless
.
Contrary to the other armed services [i.e., OKH and OKL] the OKM evaluation of the value of the mine barriers was extremely critically. They objected that the barriers would only remain effective, if the British could be prevented from clearing them. To do that required the strengthening of the Kriegsmarine covering forces for a long period. In hindsight it has to be stated that they [i.e., OKH and OKL] did not make any allowance for the clearing of the mine barriers by the British as they did for the Germans.”
Known German Minefields Actually Laid in September and their results:
Night of 1/2 September – 600 by Tannenberg, Roland, and Cobra.
Night of 6/7 September – 405 by Togo and Kaiser
Night of 8/9 September – unknown number by T5, T6, T7, and T8 off Dover
Night of 15/16 September – unknown number by T5, T6, T7, and T8 off Dover
Night of 28/29 September – unknown number by Hans Lody, Karl Galster, Erich Steinbrinck, Friedrich Ihn, Paul Jacobi off Falmouth. The field sinks: 30 Sep – one yacht (387 BRT), 3 Oct – one steamer (166 BRT), 6 Oct – one steamer (910 BRT), 6 Nov – one trawler (253 BRT), and 8 Nov – one trawler (221 BRT).
Night of 30 September/1 October – unknown number by TB Greif, Kondor, Falke and Seeadler off Dover.
Month of September – 184 by 9. Flieger Division, resulting in two MMS (Motor Minesweepers), one trawler (346 BRT), and one oiler (2,444 BRT) sunk.
Note that by a quick count, in June Nore Command alone had 19 fleet minesweepers and 148 minesweeping trawlers and Portsmouth Command had another 21 minesweeping trawlers. Plus about a 100 minesweeping drifters, yachts, and tugs.
And of course, the RN was also quite expert at mine warfare and had their own fast minelayers, 8 at Portsmouth and 2 at Dover, and were quite ready to mine the approaches of an invasion fleet.