What if Montgomery was wrong about Market Garden?

[McPherson]

Both the British & the Russians used armoured landing craft (for want of a better description) in WW1 - and the British actually used some in the amphibious landing at Suvla Bay in August 1915.
https://www.iwm.org.uk/collections/item/object/205316076
https://en.wikipedia.org/wiki/Landing_craft

I was referring to opposed landings. And if you must know, a certain General Winfield Scott used landing barges very much like an LCI to land infantry and cavalry and artillery at a place called Vera Cruz. What makes him notable is that he designed the damned things and figured out how to build and use them.

Does that count as groundwork? Even if they did forget about it for another 25 years (as per bloody usual )

It sure does. Just like Convoy was forgotten by the USN.

Higgins Boats & DUKW were what the US brought to the party in Normandy; the Brits supplied DD tanks & the Funnies. Both played important roles. Neither nation had a monopoly on innovation or execution.

Please don't forget the Canadians. They brought hundreds of new ideas to the table which both the British and Americans copied and adopted.

 

[Cryhavoc101]

The definition means "exaggeration." The claims "that the tanks were successful", as the museum curator plainly intended in his expression and use of hyperbole, was somewhat hyperbolic in its hyperbolism. He did not think much of the concept either.



The DD Shermans were the insane concept. Note the lack of a bilge pump for the D-day tanks and the fact that the British actually tested a Valentine with such a canvas skirt. They fired a machine gun at the DD Valentine (1942) under simulated landing conditions and it sank.



The DD (Sherman) concept was entirely British in notion based on their 1942 work with the Valentine.



The Americans came up with this;



Very lightly armored but it got ashore and it worked; as the Scheldt operations demonstrated against the Germans and as numerous 1944 Pacific assaults showed.

Two different solutions. The Americans rejected the DD tank (postwar) after the debacle at Omaha.

Source cite.


"Ideal conditions". McP.



The Crabs were landed directly from LCTs onto the beach, flailed for mines and shot up the German defenses before the Sherman DD's of the Sherwood Rangers, which took significant losses, even though launched from less than 600 meters offshore managed to swim ashore. Op result is 100% mission intent failure. The other sectors of the beach, the other DD Shermans were thoroughly shot up. Results I would consider "mixed".



Based on the results, with 40% of the DD Shermans not launched due to rough seas and 62% of those launched reaching shore, the mission intent was not achieved. Mission success marginal.



An accident produced another ideal outcome.



Training. Bloody awful training. Even rotten concepts and poorly thought through engineering solutions can be overcome by proper training, but we have no idea how the DD Shermans would have done at Omaha since the 95% loss of mission rate during the approach makes it impossible to see examples of DD tanks in action in any quantity in that setting.

Cumulative.



Note that despite the shambles of Omaha Beach, and including the successes of Gold and Utah, that the op-research shows guaranteed loss of 1/3 of the swimmers. That is a mission fail rate that is "successful" and mostly worked?

How about ANVIL/Dragoon?



Not too bad. At least the tanks got ashore to fight and many were lost to the usual anti-tank methods. Those that swam in suffered 12% losses. Again not too bad.

How about the Scheldt and the Rhine?



Scheldt, the Alligators (Buffaloes) worked and the DD tanks mission failed. We will hear about the Alligators again.



Hmm. The Alligators (Buffaloes) got up the banks and the engineers were able to lay causeways for the DD tanks to climb. That is ridiculous.



No numbers on the Po River and Adige River crossings, so we cannot quantify the mission. The lorry function as a claimed mission success for type in theater is of note as it is both sublime and ridiculous to use an expensive and highly specialized vehicle as a "truck". Could other choices have been made? Most certainly. At that stage of the war, Alligators would have been available.

What I see here is a lot of "mixed results" and mission fails. YMMV, but I think the case for the DD tank as a "success" is not proven. It was rejected postwar, while the Alligator's successors have been used.

Even at that, note the placid wave conditions. In rough seas, I would expect ACVs to move the equipment ship to shore.

Okay other than where LSTs drove right up to the beach (the British decided to do that on the eve of the landings due to the previous days storm) - the tanks worked in that they delivered some tanks to the beach except in one example - Omaha.

And you have obviously cherry picked data to prove you case - ignoring all the positives. It's almost 'Ambrosian'.

The alternative to the DD tank was to risk the finite number of LSTs to gun fire and mines (as well as grounding and possibly not being able to be used for the rest of the day until the tide floated them off delaying follow on landings requiring their use) 'or' no tanks.

Their were no other alternatives - 'one' of the reasons for heavy losses on Omaha? No DD Tanks.

No tanks is obviously a disaster - some tanks either landed directly onto the beach or from closer in is infinitely better than no tanks.

The Japanese were also not running 2 Regiments of Pz4s behind the beachheads - so yes a lighter 37mm armed vehicle would serve in the Pacific during the invasion of the small islands.

It would not have served at Normandy.

 

[Glyndwr01]

Higgings boat unarmoured

https://en.wikipedia.org/wiki/Landing_Craft_Assault
British armoured landing craft

https://en.wikipedia.org/wiki/Landing_craft_tank
The landing craft, tank (or tank landing craft) was an amphibious assault craft for landing tanks on beachheads. They were initially developed by the British Royal Navy and later by the United States Navy during World War II in a series of versions. Initially known as the "tank landing craft" (TLC) by the British, they later adopted the U.S. nomenclature "landing craft, tank" (LCT). The United States continued to build LCTs post-war, and used them under different designations in the Korean and Vietnam Wars.
In 1926, the first motor landing craft (MLC1) was built by the Royal Navy. It weighed 16 tons, with a draught of 6 feet 6 inches (1.98 m), and was capable of about 6 knots (11 km/h; 6.9 mph). It was later developed into the landing craft mechanised.

It was at the insistence of the British prime minister Winston Churchill in mid-1940 that the LCT was created. Its speed was 10 knots (19 km/h; 12 mph) on engines delivering about 700 hp (520 kW).[2] Designated the LCT Mark 1, 20 were ordered in July 1940 and a further 10 in October 1940.[3])

America first? I think not!

 

[McPherson]

Okay other than where LSTs drove right up to the beach (the British decided to do that on the eve of the landings due to the previous days storm) - the tanks worked in that they delivered some tanks to the beach except in one example - Omaha.

And you have obviously cherry picked data to prove you case - ignoring all the positives. It's almost 'Ambrosian'.

The alternative to the DD tank was to risk the finite number of LSTs to gun fire and mines (as well as grounding and possibly not being able to be used for the rest of the day until the tide floated them off delaying follow on landings requiring their use) 'or' no tanks.

Their were no other alternatives - 'one' of the reasons for heavy losses on Omaha? No DD Tanks.

No tanks is obviously a disaster - some tanks either landed directly onto the beach or from closer in is infinitely better than no tanks.

The Japanese were also not running 2 Regiments of Pz4s behind the beachheads - so yes a lighter 37mm armed vehicle would serve in the Pacific during the invasion of the small islands.

It would not have served at Normandy.

1. I hope I cherry picked nothing here. The author of the source cited supplied the numbers. But his numbers are accurate and so I think are my conclusions based on loss ratios and known outcomes.

2. No German tanks were on the D-day beaches or they would have been Salernoed. Japanese had plenty of AT guns in pillboxes but LVTs managed to survive that environment. And did we forget Salerno, itself? Infantry held on by their teeth and fought off a far worse panzer threat that was on the beaches there. Naval gunfire is a cure for panzers.

3. The reason the Omaha shambles was that shambles was essentially because German machine gun and mortar fire pinned down unprotected infantry in front of the sea wall. Alligators could have covered that ground quickly and unloaded breach teams to blow the wall. Worse was seen at Tarawa than Omaha, far worse as it turns out. Yet, the Marines managed. Alligators helped keep that Tarawa beachhead supplied and actually helped cover some of the assaults that got the Marines past that first line of strongpoints. Otherwise the assault would have been repulsed.

About the differences in landing craft.

4. Mortar bomb on top of an armored boat or unarmored boat= 40 dead blokes. Alternatively, open the bow hinge doors and the British blokes step off to be mowed down in ones and twos as they try to elbow past each other. Higgins ramp drops and 40 guys clear in 10 seconds and scatter. Take your choice of death if you are dialed in. MG42 gunner won't care. He'll adapt to the sitch.

5. Training, as in the troops who were supposed to get proper training in that frankly ill thought out DD tank kit, did not get it, to make the best use of what they had. I believe poor training in 'boat handling' was the reason I think the DD tanks broached in the waters off Omaha beach. Of course the lack of a bailing pump (bilge) sure did not help the tanks that were lapping water as the waves broached over them sideways. That was a bloody incompetent thing to omit bilge pumps in the engineering of that bodged up fiasco.

YMMV. I think, though, I have a good case for suggesting the first waves should have been LVTs followed by British landing barges or Higgins boats as soon as the LVT parties had overrun the beach red line.

Both the British and the American armies screwed up on that one.

 

[McPherson]

Snip.

I answered a lot of your "opinions" when I answered CH, but here's the thing.

I was referring to opposed landings. And if you must know, a certain General Winfield Scott used landing barges very much like an LCI to land infantry and cavalry and artillery at a place called Vera Cruz. What makes him notable is that he designed the damned things and figured out how to build and use them.

British landing craft at Galipolli. Does it show the British made them and did the RN forget and/or show they did not know what they were doing in WW I?

It sure does. Just like Convoy was forgotten by the USN.

And to snuff the idea that there is any "nationalism" invoked or involved in any of this analysis.

Please don't forget the Canadians. They brought hundreds of new ideas to the table which both the British and Americans copied and adopted.

That was DIEPPE. If I were going to criticize anyone American about anything when it comes to amphibious warfare, just remember, that like TARAWA was the butchers' bill in Marines to learn what did not work, so the Canadians paid the blood bill for Overlord and their lessons learned (Hobart's funnies start with THEM) was the information they brought back from that fight, paid for with combat experience and lives. Give the credit where it is really due.

McP.

 

[Dave Shoup]

Really? One was reroled as infantry for Greece in 1944; one was converted to LVTs for the Rhine crossings; it doesn't look like simply a shortage of tankers.

In terms of armored formations the British committed to action in Europe in 1943-45, the British disbanded one (1st Armoured) of the five combat armoured divisions (Guards, 1st, 6th, 7th, and 11 armoured divisions) in the order of battle. So, 20 percent of the available British armoured divisions were lost (administratively, not in action) as of 28 Oct. 1944.

Breaking it down to armoured brigades, of the 19 armoured brigades (including armoured brigade groups and tank brigades) the British committed to Europe in 1943-45 (five divisional armoured brigades, the 5th Guards, 2nd, 22nd, 26th, and 29th) and 14 separate (1st Tank, 4th Armoured, 6th Guards, 7th, 8th, 9th, 21st, 23rd, 25th, 27th, 30th, 31st, 33rd, and 34th) the British disbanded the 1st (Oct., 1944) and 27th (July, 1944), downgraded the 23rd to what amounted to a motorized constabulary brigade (Oct., 1944) for service as a garrison force, and converted the 25th to an armoured engineer brigade (Jan. 1945).

So, again, they reduced the armored formations by four of 19 brigades (in total) - almost 20 percent.

All of the above is from Joslen.

Those realities do not suggest an army that had an excess of armoured battalion and tank company commanders, staffers, maintainers, and drivers, gunners, and loaders, does it?

The equivalent would have been if the US Army broke up three of the 16 armored divisions deployed to Europe in 1943-45 because of a need for replacements. Or the French had broken up one of the three armored divisions they had in Europe in 1944-45. Or the Canadians, one of the four armoured brigades (one each in the 4th and 5th armoured divisions and two separate brigades) they had in the Canadian Army in Europe in 1944-45.

 

[Dave Shoup]

3. The reason the Omaha shambles was that shambles was essentially because German machine gun and mortar fire pinned down unprotected infantry in front of the sea wall.

Ahem. The Atlantic Wall was such a formidable obstacle the 1st and 29th divisions were past it by mid-morning.

It was a brutal fight, and the infantry, tankers, and engineers who landed there in the morning of June 6 deserve all the credit and glory - but Omaha, as bad as it was, was won well before noontime.

 

[McPherson]

Ahem. The Atlantic Wall was such a formidable obstacle the 1st and 29th divisions were past it by mid-morning.

It was a brutal fight, and the infantry, tankers, and engineers who landed there in the morning of June 6 deserve all the credit and glory - but Omaha, as bad as it was, was won well before noontime.

Three cheers for the USN who provided the cover fire for the final assaults. It took nerve to run the destroyers that far into the shallows.

 

[Dave Shoup]

Three cheers for the USN who provided the cover fire for the final assaults. It took nerve to run the destroyers that far into the shallows.

Sure, but NGFS was a given. The USN and RN made the difference on more than one occasion.

 

[viperjock]

No one has mentioned the Ferry in the village of Driel on the southern bank of the Rhine. Allied planners completely overlooked the ferry in their planning for Market-Garden. Luckily the Germans ignored it as well. The British only noticed the ferry toward the end of the battle when the 1st Airborne was trapped in the Osterbeek perimeter. The Germans only occupied the high ground overlooking the ferry site when they were tightening the noose around the British Airborne.
If Allied intelligence had noticed the ferry, at the minimum the British should have seized the ferry upon landing on September 17 and established a forward outpost in Driel.
If the Nijmegen Bridge was captured on September 17 and contact was still lost between Browning and the Red Devils a patrol could have been sent North. Gavin could have sent a patrol from the 82nd accompanied by a staff officer from Browning’s HQ. If in this scenario the ferry was still forgotten in the planning stage maybe the Americans could have found the ferry and Gavin could have recommended a plan B to get into Arnhem.
One more suggestion:
A Dutch reconnaissance unit should attached to XXX Corps. The Dutch were completely shut out of Market-Garden except for liaison officers. A fast moving recon unit made up of Free Dutch troops could have been given the mission of establishing contact with Airborne units. Their mission would be to be the operation’s eyes and ears. They would avoid contact with the Germans as much as possible. I am sure Dutch Soldiers from the region could have been found.

 

[edgeworthy]

I was referring to opposed landings. And if you must know, a certain General Winfield Scott used landing barges very much like an LCI to land infantry and cavalry and artillery at a place called Vera Cruz. What makes him notable is that he designed the damned things and figured out how to build and use them.
.

Sulva Bay wasn't an opposed landing? That's an interesting concept!

General Wolfe used the first specially built landing craft to traverse the St Lawrence river during the Siege of Quebec in 1759.

Napoleon ordered the construction of hundreds of specialist amphibious assault ships for the Flottille de Boulogne
https://en.wikipedia.org/wiki/Flottille_de_Boulogne

 

[McPherson]

Sulva Bay wasn't an opposed landing? That's an interesting concept!

General Wolfe used the first specially built landing craft to traverse the St Lawrence river during the Siege of Quebec in 1759.

Napoleon ordered the construction of hundreds of specialist amphibious assault ships for the Flottille de Boulogne
https://en.wikipedia.org/wiki/Flottille_de_Boulogne

1. Suvla Bay cannot be actually called a seriously opposed landing. The British walked ashore in absolute chaos (It was dark.) about 10+ to 1 against minimal Turk opposition and they screwed everything up not even reaching their red lines (1000 meters inland). Then the Turks and the British played footsie for a week before both sides finally bogged down in trenches. People who came ashore at Casablanca, North Africa (similar chaos) would have laughed at both sides at Suvla.

British war correspondent Ellis Ashmead-Bartlett witnessed the landing shortly after dawn from the transport Minneapolis. While he could hear the fighting continuing at Anzac, Suvla was comparatively quiet and "no firm hand appeared to control this mass of men suddenly dumped on an unknown shore." The British official history, written by Captain Cecil Aspinall-Oglander who was on Hamilton's staff, was blunt in its assessment; "It was now broad daylight and the situation in Suvla Bay was verging on chaos."

2. Napoleon's barges like the ones intended for the later unmentionable sea mammal were badly designed and would have drowned his soldiers in an own goal. At least the Higgins boats were seaworthy and were tested.

3. About those British LCAs... also tested...

Looks to me that a Higgins boat offered more protection than what I see (^^^). But that is an optical and my delusion, right?

 

[Dave Shoup]

As far as getting armor ashore in an assault, presumably the simple approach would have been sufficient...

 

[Aber]

So, again, they reduced the armored formations by four of 19 brigades (in total) - almost 20 percent.

And the reduction in infantry was similar - the British Army had an overall manpower issue, as well explored in various threads.

The equivalent would have been if the US Army broke up three of the 16 armored divisions deployed to Europe in 1943-45 because of a need for replacements

Not really, as 8 of those only entered combat after mid November 1944, and 3 only after the Rhine had been crossed in 1945. The British Army was at peak strength in Normandy in 1944 and was a wasting asset after that; the US Army did not get all its divisions into combat before the end of the war.

 

[Aber]

3. The reason the Omaha shambles was that shambles was essentially because German machine gun and mortar fire pinned down unprotected infantry in front of the sea wall.

Yes, the assault stalled with the attackers vulnerable to artillery and mortars.

Alligators could have covered that ground quickly and unloaded breach teams to blow the wall.

Up to a point - first they have to clear the beach obstacles eg



The biggest single difference between the US and British beaches were the AVREs, and the protection they gave the beach engineers in clearing obstacles and getting over the seawall.

As far as getting armor ashore in an assault, presumably the simple approach would have been sufficient...

Yes, but that involves an obvious large craft approaching the beach; part of the attraction of the DD was that it looked non-threatening to beach observers until it landed and dropped the floatation screen.

 

[McPherson]

Yes, the assault stalled with the attackers vulnerable to artillery and mortars.

Up to a point - first they have to clear the beach obstacles eg

View attachment 493997

The biggest single difference between the US and British beaches were the AVREs, and the protection they gave the beach engineers in clearing obstacles and getting over the seawall.

Yes, but that involves an obvious large craft approaching the beach; part of the attraction of the DD was that it looked non-threatening to beach observers until it landed and dropped the floatation screen.

If the flotation works, your AVRES can move forward. if the flotation works, your tanks can move forward, if the floatation works your heavy equipment can move forward.

What if you screwed the ground pressure measurement up? Then you are left with stuck machines stranded and only men. One of the lessons of amphibious assault Pacific style is that you better know the ground pressure of the beach. Tarawa lesson #4.

As for blowing beach obstacles, the LVTs carried sappers forward in later assaults. Tarawa lesson #5.

Anything swimming toward the beach, the Japanese and any other sane defender opposing a landing, regardless of how "harmless it looks", will shoot with gusto. Tarawa lesson #6.

 

[Dave Shoup]

And the reduction in infantry was similar - the British Army had an overall manpower issue, as well explored in various threads. Not really, as 8 of those only entered combat after mid November 1944, and 3 only after the Rhine had been crossed in 1945. The British Army was at peak strength in Normandy in 1944 and was a wasting asset after that; the US Army did not get all its divisions into combat before the end of the war.

Yes, the British Army had a manpower crisis in 1943-45 in the ETO, and that reality is well known. The question, given that reality, is did the British do the most with the manpower they had access to in 1943-45 for the Allied cause? As a subsidiary of that, did diverting seven RAC battalion equivalents into the 79th in 1944 make sense, given the availability of RE personnel to provide crews for CEVs?

So in the reality where the British actually did disband the 1st Armoured Division (20 percent of the available British armoured divisions) and the separate 1st Tank and 27th Armoured brigades, along with sidelining the 23rd and 25th armoured brigades (roughly the equivalent 20 percent of the available British armoured brigades, both divisional and separate), would an equivalent reduction in Allied armored formations have been accepted?

Presumably not...

As far as the US armored divisions, um, not quite. "In combat" is an interesting requirement; by that measure, the British 79th Armoured Division obviously doesn't "count" as a combat formation, since it never saw action as a division. Based on deployment dates, all but three of the 16 US armored divisions were in theater before 1945.

US 1st Armored - in theater, 05/42 (UK); in combat or deployed to mainland Europe or the MTO, 11/42 (FNA);
2nd Armored - 11/42; 11/42 (FNA);
3rd - 09/43; 06/44;
4th - 01/44; 07/44;
5th - 02/44; 07/44;
6th - 02/44; 07/44;
7th - 06/44; 08/44;
8th - 11/44; 01/45;
9th - 09/44; 10/44;
10th - 09/44; 09/44;
11th - 11/44; 12/44;
12th - 10/44; 11/44;
13th - 01/45; 01/45;
14th - 10/44; 10/44;
16th - 02/45; 02/45;
20th - 02/45; 02/45.

As far as the equivalent of the British Army's separate armoured and tank brigades in the US Army, the separate armoured groups, go, of the 20 numbered armoured groups activated between 1941 and 1944, three were activated in Hawaii specifically for the Pacific War, and all three saw action; 17 were activated in the US, and of those, 11 went to the MTO/ETO and one to the Pacific. Of the five others, two were still in existence by VJ Day and in training for deployment to the Pacific. Two of the remaining three were deactivated in 1944 and the third in March, 1945, after serving as a training formation. None of 15 that went overseas were disbanded in theater.

As far as US divisions not seeing action before VJ Day, there were a grand total of three, all of which - however - were deployed into active theaters before the end of the war. The 13th Airborne was in France from February, 1945, and formed the only truly "fresh" infantry division in the SHAEF strategic reserve until the end of the war; the 98th Division was in the Pacific in April, 1944, and was earmarked for DOWNFALL; and the 2nd Cavalry, which was in North Africa in March, 1944, and was broken up for service units to sustain the MTO and Sixth Army Group in May, 1944.

Sources for above are Joslen and Stanton.

 

[Dave Shoup]

Yes, but that involves an obvious large craft approaching the beach; part of the attraction of the DD was that it looked non-threatening to beach observers until it landed and dropped the flotation screen.

LCTs and LCIs were used as assault craft on multiple beachheads. It's what they were designed for...

 

[marathag]

I was referring to opposed landings. And if you must know, a certain General Winfield Scott used landing barges very much like an LCI to land infantry and cavalry and artillery at a place called Vera Cruz.

One of the reason the Duke of Wellington called him the finest living Soldiers of the age.

 

[Cryhavoc101]

1. I hope I cherry picked nothing here. The author of the source cited supplied the numbers. But his numbers are accurate and so I think are my conclusions based on loss ratios and known outcomes.

2. No German tanks were on the D-day beaches or they would have been Salernoed. Japanese had plenty of AT guns in pillboxes but LVTs managed to survive that environment. And did we forget Salerno, itself? Infantry held on by their teeth and fought off a far worse panzer threat that was on the beaches there. Naval gunfire is a cure for panzers.

3. The reason the Omaha shambles was that shambles was essentially because German machine gun and mortar fire pinned down unprotected infantry in front of the sea wall. Alligators could have covered that ground quickly and unloaded breach teams to blow the wall. Worse was seen at Tarawa than Omaha, far worse as it turns out. Yet, the Marines managed. Alligators helped keep that Tarawa beachhead supplied and actually helped cover some of the assaults that got the Marines past that first line of strongpoints. Otherwise the assault would have been repulsed.

About the differences in landing craft.

4. Mortar bomb on top of an armored boat or unarmored boat= 40 dead blokes. Alternatively, open the bow hinge doors and the British blokes step off to be mowed down in ones and twos as they try to elbow past each other. Higgins ramp drops and 40 guys clear in 10 seconds and scatter. Take your choice of death if you are dialed in. MG42 gunner won't care. He'll adapt to the sitch.

5. Training, as in the troops who were supposed to get proper training in that frankly ill thought out DD tank kit, did not get it, to make the best use of what they had. I believe poor training in 'boat handling' was the reason I think the DD tanks broached in the waters off Omaha beach. Of course the lack of a bailing pump (bilge) sure did not help the tanks that were lapping water as the waves broached over them sideways. That was a bloody incompetent thing to omit bilge pumps in the engineering of that bodged up fiasco.

YMMV. I think, though, I have a good case for suggesting the first waves should have been LVTs followed by British landing barges or Higgins boats as soon as the LVT parties had overrun the beach red line.

Both the British and the American armies screwed up on that one.

Firstly apologies I was quite grumpy yesterday and that has come across in my response.

But you have picked all the failures and presented them alone without also showing that the damn thing worked regardless of said failures

You shared David Fletcher's very entertaining talk on the DD Tank as proof that it was a failure? He says no such thing! It wasn't perfect - but it worked.

But the point I wanted to make is that DD tanks was not a single answer to a single problem it was one of several answers to several problems - in other words it would have been foolish to rely upon LST delivered AFVs alone.

That LST delivered tanks successfully achieved the mission is fantastic but the DD-Tanks still arrived - that the Crabs managed to perform one of the Tank mission in spite of their own - shows that there was multiple redundancies

Especially as the original plan was to not risk the LSTs in the initial wave and to rely upon the DD tanks - it was only because of the Storm on the night of the 4th and 5th June that the British on the evening of the 5th decided to risk them and either drop the tanks into the surf or go straight in and deploy them on the beach.

The failure point here is that for whatever reason the OC making the decision for the US DD Tank Deployment choose not to risk the LSTs at all and deployed the DDs well beyond the range they should have been deployed from the beach in a sea state they should not have been operating in.

What would have happened if the Shore based anti ship batteries had proven to be as big a threat as had been feared and either sunk the larger LSTs or forced them to back off?

Each lost LST was pretty much irreplaceable in the context of the Normandy campaign and the loss of even a handful might have had serious repercussions to the campaign as a whole and not just the first days assault landings.

So I do understand some of the constraints that led to that decision - however history has shown it to have been the wrong decision.

Alligators might very well have been able to provide the support you talk of - DD tanks certain would have and did on other beaches and beyond such as at Utah when they allowed the assaulting forces to break inland earlier than would have been the case if the infantry had been obliged to do it alone.

.50 cal guns are great - 75mm HE from an M3 gun is better

DD tanks were possibly not a great solution to getting armor on the beach with the assaulting infantry but the alternative of not having a solution is f&^*ing terrible and blood would have to be used instead of Steel (as it was at Omaha)

Were Alligators used at Normandy - I know they were used later on ins subsequent ops?

As for DD Tanks not being used post war.

I am not surprised they were a specialist vehicle designed for a particular job operated by a specialist Regiment/or Regiments and MBTs became too heavy to practicably become DD tanks

Alternative methods are used instead

I note that Crocs and AVREs and Crabs etc have not been operated in massed formations since either except in smaller units and today just do not seem to exist - those jobs being carried out by none tank vehicles (or in the case of flame tank not at all)