D-3: Mine Warfare Operations: Approach March

D-Day is not going to happen if the mines aren't swept. It is hard work and an honourable job, but also a boring, quotidian one. Quotidian is boring: Rick Atkinson deals with it in a single paragraph on page 37 of Guns at Last Light (2013; (36--7). The largest mine warfare effort in history with the gathering of "some 255" vessels in Area Z, the marshalling area south of the Isle of Wight from whence the convoys will make their departures to the Norman shore. One paragraph. What else is there to say?

This is the "Tree" class trawler Acacia (Image credit: Wikipedia). Six of 20 taken up from the Ardrossan Dockyard Company were lost in WWII, an honourable total from amongst the over 400 trawlers either taken up from the British fishing industry or built to the Admiralty account, although "trawler" unambiguously identifies a working boat, a relatively small craft intended to be used to fish the open banks with large nets dragged behind the boat. It is a big business in Britain. Though, to be fair, it is a big business most everywhere in the world with a seacoast. 

I have taken this image from a fairly typical book about the fisheries of Britain , typical in the sense that it salutes the productivity of the industry, notes its historical importance to Britain's seapower, and then switches tone with an elegant pirouette from the vital importance of the business to recipes that will encourage people to eat more fish. Apparently, you can have it both ways. I have talked about the industry's hard dynamics elsewhere

The fisheries are a hard business, is what I am saying.  What it appears that I have not talked about is the way that the Admiralty subsidised the business, which was by enrolling fishermen in the Royal Naval Reserve and subsidising the outfitting of a standard type of "Admiralty" trawler with radio direction finders and depth sounders. High technology for 1939! It also set aside 250 simple sonar sets to equip the fleet on mobilisation. So they could fish for mines instead of herring! While German fishermen laid them. "You know, what this town needs is two lawyers."

I must have talked about this before, even if I can't find the details. Anyway, point is, on the outbreak of war, Britain was ready to mobilise a vast fleet of Captains Courageous to do the hard work of sweeping up German mines.

(If you don't recognise the moment, the extended Youtube clip is here.* The USN was not; not that I blame them. Out of the scarce money that Congress allocated the United States Navy, why, exactly, should so much of it go to fishing towns to pay men to do things they were going to do already, so that they would be ready to fight a kind of war that America would not face? It is almost as hard to lay mines as to sweep them, after all, and no-one was going to cross the Atlantic to launch a largescale offensive mine warfare campaign against the United States. 

That's why this ships like this are British:*

Not that the USN was short of minesweepers to do its part in Operation Neptune by 1944. Having learned from the fiasco of the "mass-produced" Eagle Boat in World War I, yet another disastrous Ford Motor Company would-be intervention in modern war, the Navy Department commissioned a British design and than some of its own, and dealt with as many mines as the enemy laid. American fishermen were more likely to go to war on amphibious craft than on minesweepers, but that's fine. One way or another, the needed human resources were mobilised for an attritional campaign in coastal waters that culminated in ...well, you know where it culminated.

To prevent an amphibious operation, you only need to deny the sea to the enemy. Rowed gunboats (and submarines), polished shields and some long-forgotten naptha compound of antiquity (unless the "Byzantines" really did invent gunpowder) have all been invoked by the imaginative, but nothing is so quotidian to the life of the sea as the naval mine.  Poachers have been making their livelihoods from the traps of others along the banks and shoals of the inshore sea for as long as people have been evasive about what they do for a living. Why not give them more than they're looking for? An infernal device will do.

Quotidian is boring: Rick Atkinson deals with the Allied mine warfare effort in a single paragraph on page 37 of Guns at Last Light (2013). He begins his paragraph-long account (36--7)  of the largest mine warfare effort in history with the gathering of "some 255" vessels in Area Z, the marshalling area south of the Isle of Wight from whence the convoys will make their departures to the Norman shore.

The Ministry of Defence Operation Neptune website omits credit to Gordon Smith, adapting a map from Roskill, War at Sea

The United States Navy Naval Historical Center gives us a little more specific information: 

The total strength of Allied minesweepers, engaged in the assault,² was 255 vessels. This force comprised (footnotes are internal to the originating webpage). I added the Wiki links, with the aim of illustrating the human strength of the flotillas, well into the five figures. Note specifically the failed attempt to cut the complement back from Halcyon to Bangor to Algerine. Sweeping mines took far more work in 1944 than it did in 1918:

1. twelve fleet minesweeping flotillas of 9 ships per flotilla (1, 2, 3);³
2. six flotillas (of 10 ships each) of YMS type motor mine sweepers;⁴
3. seven flotillas (of ten ships each) of British type motor mine sweepers;⁵
4. four groups (of five ships each) of mine sweeping trawlers;⁶
5. thirty-six R.N. mine sweeping motor launches;
6. forty-eight R.N. danlayers; and
7. nine miscellaneous supporting ships and craft.

but then looks back to "last Sunday," when the Royal Navy laid "secretly planted underwater sonic beacons" which now activate to guide the sweeping flotillas into the entrances of the pre-selected swept channels. Notice that this implies that the beacons can be activated remotely, as the first sweeps were cancelled on receipt of an unfavourable weather forecast at 0840, June 4. It is an impressive bit of electronic engineering, and one that I have never heard of elsewhere, unlike the LORAN (in this context QH and QM) that makes this precision of navigation possible in the first place. 

Boring is vital: The initiative belongs to the would-be sea denier. The Germans were always able to hold something back. In  Michael Melvin's words, “the Germans were always one step ahead.” The mines did not even have to work. German coastal defences covered the inshore minefields. The minefields covered the defences.  German surface forces did not have to sink Allied ships, only lay mines. The residual threat meant that the Allies had to deny German light forces the invasion waters, not brush them aside. The DD clashes of spring 1944 flowed from this. 

Denial, delay: it is not about ships sunk, but tonnage landed. Nevertheless, 116 mines were swept on the 4th–6th, and losses 4 June–22 June were BYMS 2069, YMS 167, MMS 297, USS Osprey, MMS 221, MMS 229, YMS 304, MMS 8. (1) It is about resources used. There were 955 minesweepers in home waters and 1520 abroad in “1944.” (2)

Nor, as usual, have we begun to scratch the surface:

We are the D-Day Divers...

(1). Michael J. Melvin, Minesweeper (Worcester: Square One, 1991),

(2). Eric Grove, ed. Defeat of the Enemy Attack on Shipping, 1939—1945: A Revised Edition of the Naval Staff History Volumes IA (Texts and Appendices) and IB (Plans and Tables) (Aldershot, Hamps.: Ashgate, 1997; original edition 1957), which is a publication of the Naval Records Society, and I note the call number DA 70.A1 V. 137 because God only knows how this book is cited,

*Oh, no! Spencer Tracy! Kind of subtext-y, in retrospect.