June vs May Decison for Op Neptune

The books frequently mention that the original target date for Operation Neptune was set back from 1 May to 1 June 1944. The desire for five vs four assualt beaches and the need for another delivery of landing craft is usually refered to. But, those are the only details I have encountered. Does any one have any deeper insight into the reasons and timing of this decsion?

I'm particularly interested into when this change was considered and the actual decision made. Any recommended sources on this are welcome, as would be a quick sketch from anyone knowledgeable about it.

Thanks

 

I thought I rememberd weather playing a part as well or was this earlier in the planning phase?

 

Additionally to the weather there were some other factors they considered, like the phase of the moon-relative to the tides, the volume of the supplies they have ready to be sent and the level of the training of the forces in landing under bad weather conditions and heavy enemy's fire.

For more info i suggest the following links:
OMAHA BEACHHEAD OPERATION NEPTUNE
Operation Neptune: Facts, Discussion Forum, and Encyclopedia Article
Operation NEPTUNE (Naval Aspects of Operation OVERLORD) Administrative History (1948).

 

Additionally to the weather there were some other factors they considered, like the phase of the moon-relative to the tides, the volume of the supplies they have ready to be sent and the level of the training of the forces in landing under bad weather conditions and heavy enemy's fire.

For more info i suggest the following links:
OMAHA BEACHHEAD OPERATION NEPTUNE
Operation Neptune: Facts, Discussion Forum, and Encyclopedia Article
Operation NEPTUNE (Naval Aspects of Operation OVERLORD) Administrative History (1948).

 

Seems like there were quite many problems...Not a surprise really...

The air plan, finally received on 12 May 1944....

It became increasingly apparent throughout April and May that the MULBERRY program was falling behind schedule.....

In the six weeks before D-day, the enemy intensified his minelaying program off the South Coast of England, using aircraft on a larger scale than for over two years. He also employed two new types of mines. Minelaying was, however, confined to moonless periods. As the last week before invasion was in the new moon period, the mines laid were not beyond tha capabillties of the minesweeping resources of the Home Commands. "Had D-day been in such a period it is doubtful whether the Portsmouth channels could have been cleared in time."

Operation NEPTUNE (Naval Aspects of Operation OVERLORD) Administrative History (1948).

 

Sorry, can't get that link Kia,is it American?,cheers.

 

It is the official site of the US Navy. For some reason I cannot understand, it is not available. Maybe this is temporary. Anyway please try this link: www.*navy.*mil
and you may find the way to the history sector.

 

The decision to delay Neptune to June 1 was made on January 31. Because tides and moon had to cooperate for airborne, air, and navy, the June 1 date was an approximation for which June 5, 6, and 7 would work, assuming the weather cooperated. Here's what "The Cross-Channel Attack" had to say:

On 5 January General Smith cabled General Eisenhower in Washington to report Montgomery's argument for a

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stronger and broader O[SIZE=-1]VERLORD[/SIZE] assault.[SIZE=-1]23[/SIZE] "Additional lift," he said, "can only be obtained at the expense of A[SIZE=-1]NVIL[/SIZE]. Montgomery is insistent on the immediate recommendation to abandon A[SIZE=-1]NVIL[/SIZE] except as a threat previously agreed upon by the COSSAC and AFHQ staffs before the reinforcement in landing craft was decided upon at the Cairo Conference." Smith added that, although he had refused to make such a recommendation without General Eisenhower's "personal approval," he nevertheless agreed with it. He felt that A[SIZE=-1]NVIL[/SIZE] as a one-division threat would be just as effective as the contemplated three-division assault. In this General Morgan and the bulk of the planners in England concurred.[SIZE=-1]24[/SIZE] Morgan, like most of the planners, believed the A[SIZE=-1]NVIL[/SIZE] assault, as planned, was so remote from the O[SIZE=-1]VERLORD[/SIZE] area and from any military objectives vital to the Germans that the enemy would not find it worth while to divert more than two or three divisions from the main battle in the north in order to cope with it. The same diversion, he thought, could be achieved by a threat requiring amphibious lift for only one division. Eisenhower agreed that "O[SIZE=-1]VERLORD[/SIZE] must be more broadly based" but he did not think A[SIZE=-1]NVIL[/SIZE] as a threat would be as effective as the operation itself.[SIZE=-1]25[/SIZE] Pending the outcome of the debate thus initiated, planners proceeded with an examination of the additional resources needed for the "Montgomery plan" and the implications of finding them.[SIZE=-1]26[/SIZE] To get the landing craft they estimated it would be necessary to return half of the two-division A[SIZE=-1]NVIL[/SIZE] lift to the United Kingdom. In addition the O[SIZE=-1]VERLORD[/SIZE] target date would have to be postponed from 1 May to 1 June in order to secure an additional month's production, and the number of vehicles per assault division would need to be cut to 2,500.[SIZE=-1]27[/SIZE] The broadened assault front would also increase the fighter plane commitment by eight squadrons. To lift a complete airborne division instead of the two-thirds originally planned would necessitate finding 200 more transport aircraft.[SIZE=-1]28[/SIZE] The bill for the principal types of landing craft--as always the critical commodity--included an additional 72 LCI (L) 's, 47 LST's, and 144 LCT's.[SIZE=-1]29[/SIZE] The bill was submitted to the Combined Chiefs of Staff by General Eisenhower a week after he arrived in London. He was anxious that it be met, if possible, without interfering with A[SIZE=-1]NVIL[/SIZE] and indicated his willingness to postpone O[SIZE=-1]VERLORD[/SIZE] until after 1 June even though that meant the loss
​

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of a month of good campaigning weather. The postponement was seconded by the British Chiefs of Staff, and agreed to by the U. S. Joint Chiefs of Staff on 31 January. Besides insuring extra landing craft, the later date would increase the chances of favorable weather on the Russian front and thus make it possible for more closely coordinated action between the Allies.[SIZE=-1]30[/SIZE]
​

 

It opened right up for me, both yesterday and just now when I checked again. Don't know why it isn't opening for some others.

 

So the reason that the assault went in in June,was mainly because of the lack of various landing craft?,would that be an accurate assessment?,cheers.

 

Some .mil sites are not accessable outside the US.

 

Did any landing ships,craft etc that were moored in British ports awaiting Overlord,get transferred to the Med for use in Dragoon and/or possible amphibious operations in Italy?,cheers.

 

It depends on when you considering them being moved. Landing craft were at least retained, if not moved or diverted to the Mediterranean for the Anzio operation (January 1944). The need to reinforce and supply Anzio through late May 1944 had to have negative effects on the lift available for OVERLORD and ANVIL.

 

So the answer is yes,am I correct?

 

The answer is yes, landing craft were diverted to the Med at the expense of Overlord, but not for ANVIL/DRAGOON, rather for SHINGLE (Anzio). ANVIL was originally planned as a two division landing simultaneous with OVERLORD. The demands of maintaining the Anzio force as well as the additional forces in Normandy, meant that ANVIL had to be postponed. The Anzio breakout in May and the capture and opening of Cherbourg in June/July freed up enough landing craft to allow DRAGOON (the invasion formerly known as ANVIL) to be carried out as a three division landing in August.

 

Thanks canambridge.It's one of those big"What if's".What if the Allies had landed in May?,the coastal defences would be less fearsome perhaps?.I don't know if there were more German units in Normandy?.if there were less German units,perhaps the Allies could have taken strategic targets faster?,and of course the Allied build up may have been faster?.There might have been a faster logistical build up too?,what if eh?. But June it was,and we know the rest........cheers.