Southwick House and D-Day: Events of 1944

Author

Boxall-Hunt, Brian OBE, Commander, RN

Subjects

History - WW2, WWI operations

Tags

D-Day, D-Day:Overlord, D-Day:Neptune

RAN Ships

None noted.

Publication

March 2004 edition of the Naval Historical Review (all rights reserved)

Combined operations ships and craft varied from large converted liners (Landing Ships Infantry) to floating docks and amphibious tanks. Four years of accumulated UK/US experience of amphibious warfare had gone into the 4,126 vessels, about 75% of which wore the White Ensign, although substantial numbers were American-built and armed under the Lend/Lease agreement. Actual numbers of LSTs and LCTs available to the Allies is shown below and gives a good picture of the balance between Pacific and European Theatres.

LCTs And LSTs Serviceable and Operational 1st June 1944:

The table also quite clearly shows why, on D-Day, British LCTs were landing US troops on US beaches and US LSTs was landing British troops on British beaches. There were also hundreds of other specialist vessels – for channel marking, salvage, cable-laying, towing and supplying oil, coal, water, ammunition etc, and for a constant patrol off the enemy coast. On D-Day the Western (UK) Task Force had 931 ships and the eastern (British) Task Force had 1,796, including everything that crossed the channel ‘on its own bottom’.

*All US built

As far as the enemy threat was concerned, the German naval forces, under Admiral Krancke, Commander Naval Group West, were weak in surface ships, but likely to try mining and submarine attacks. There were about 30 E-boats and 10 destroyers or torpedo boats based on the channel coast plus at least 50 U-boats in Biscay bases. The mining threat was considered the worst and, indeed, a barrage of mines had been laid by the Germans in the spring of 1944, fitted with flooders to sink them by mid-May when it was assumed that the invasion danger would be over for the year. The Germans had invented pressure mines early in the war but had not yet used them for fear of the secret leaking out and similar ones being laid in the Baltic by the Allies. Four thousand were manufactured for use against the invasion. Fifty were kept at Le Mans, but Goering decided (before the invasion) that Le Mans might be captured and ordered them to be returned to Germany. This transfer was completed by 4th June 1944 and this delayed their being used by what may have been a decisive amount. Very elaborate arrangements were made by the Allies for cross-channel sweeping and shallow water clearance off the beaches. Nearly 3,000 minesweepers were detailed, all being the responsibility of the Royal Navy.

Against U-boats, four support groups, additional to the normal convoy escorts, were allocated to the Plymouth Command and six more with three escort carriers were cruising west of Land’s End to be ready if needed.

For anti-E-boat and anti-destroyer work on the cross-channel routes, 24 destroyers and frigates were based on the flanks and 22 flotillas of RN and USN MGBs, MTBs and MLs were allocated to the Southern naval commands.

For anti-aircraft protection there were special AA ships in each assault force and fighter direction ships with the latest radar for control of shore-based fighters.

There were two Mulberrys (artificial harbours), one ‘A’ for the British section and one ‘B’ for the American. Both were British built (‘A’ was a wreck after 10 days’ use and was not repaired but ‘B’ suffered less damage and was rebuilt). For fuel there was PLUTO (Pipe Line Under The Ocean), laid from the Isle of Wight to Normandy and later from Dover to the Calais Area. There were also Gooseberries, which were craft shelters. These consisted of 400 units of various types, including 55 old merchant ships and a few obsolete warships to be sunk to form sections of the harbour breakwaters. Over 160 tugs were needed to tow them.

Decisions Prior to D-Day:

From 1st June 1944, then planned as D-4, meetings were held in Southwick House at 0400 and 2130 daily (times throughout, including on the Wall Map, are Double British Summer Time-Zone-2) to discuss the weather, which became a preoccupation for the planning team. With D-Day planned as 5th June, the first sailing had to be on 3rd. The forecasts on Saturday 3rd June were not at all favourable, with gale force winds and heavy rain expected. At 0400 on 4th, the weather was bad but with a prospect of some improvement, and Montgomery wanted to press on. Save for him, however, all opinion was against this course and Eisenhower took the decision to postpone the assault for 24 hours. (At this time the leading minesweepers were within 35 miles of the beaches and two midget submarines were already in position as navigational markers off beaches GOLD and SWORD).