The Pinch/ 4 Rotor. The other reason to attack Dieppe?

David O’Keefe has another theory on the raid of Dieppe and seems to be well resourced.

Firstly a lot of research was and still is hidden in archive, the Bletchley efforts only started to get know in the 1970s and as the spionage activities went on after WW2 there wasn’t a real impetus to declassify.

To me: I don’t think the invasion of Dieppe was done for ONLY one reason. That is not how decisions work, there are many pluses and minuses. Historians tend to pick up a narrative and thread in time which makes sense and is easy to follow.

For me the “trial invasion” seems unsatisfactory. But like the Parshall rewrite of Midway it is very hard for another version to be accepted.

See below:
One Day in August | By David O’ Keefe - YouTube


When I was in Highschool we learned a lot about Dieppe and while some of it might be wishful thinking on our part as Canadians some of it was proven I’ll stick with the proven stuff.

-Dieppe as many know was used as a trial as nobody had ever done any large scale landings before and there were a lot of unknowns at the time. This included time it took to get to shore, how to get vehicles and equipment ashore under fire, would air superiority be a factor, how large of a naval force and supply chain was required and several other factors. We also know the hard lessons that were learned at Dieppe and were used for the planning of the invasion of North Africa.

-this was also an intelligence gathering mission as the Canadians were to storm the German areas command offices and get as much intelligence as possible and were to capture any Germans especially officers for intel gathering.

-this was also to be used as a morale booster not only for the civilians, but the government and military as while there had been successes in the Mediterranean it was far from home. While we now know what happened during that time both the press and government communiques spun it as positive raid although it was a military disaster.


-*** this one is up for debate as I learned this in school and could be wrong. As to why Canadians were used instead of Battle tested British troops supposedly the Canadian government and military pushed both the British military and government to lead this raid as both a morale booster for Canadians and because Canadian soldiers had been languishing in Britain for almost 3 years at this point with nothing to do but train and be bored.


Thanks for the reply.

Could it be that both stories are true?

1 While the enigma rotors were known the whole intelligence actions were not very well know as the Allies kept it secret and the people involved learned there as a death penalty for talking about it. (Source for me is a Bletchley girl who kept her mouth shut untill the 70s when books came out).

2 Dieppe was a huge raid, I think it is feasible that intelligence gathering was part of the raid anyway. So apart from the Canadian forces who took the town a lot of special forces also went there with haversacks to collect data and e.g. the for rotor enigma.

Where O Keefe is probably wrong is claiming that the 4-rotor was the only reason. That is “historical single line narrative thinking” there were more reasons for the raid and also arguments against (eg what forces are available and is their political buy-in).

The whole intelligence part might have been buried in archives for too long and as that part also didn’t work out the Allies were not keen on telling the world. They even kept the methods Bletchley used secret as the intelligence wars didn’t stop in 1945?

Does that make sense? Tell me if I go wrong anywhere in this thought process.


Oops. I didn’t see this. Sorry


I agree with you that this is probably way too easy to just attribute this to one reason. I think it was a primary reason for some of the people assigned to the invasion but most wouldn’t have had a clue and that includes those who were writing the orders.


No worries, greetings from Dieppe and I am glad more people read O’Keefe. I am actually hereon a short trip. Incredibly difficult terrain to attack. Ironically Dieppe is also in Normandy and the Germans never expected a second attack in Normandy.


We have to remember that Gallipolli.had given large-scale amphibious operations a bad name. In 1942 they were still viewed dimly. The Americans have taken some steps to implement new vehicles and tactics in the Pacific, but in Europe where land reinforcement us much easier it is still risky. Hindsight and all that.


I wouldn’t give all the credit to the Americans. They were working closely with the British to get the requirements right, then we would build the hell out of them.


I’d still give the majority as the Americans conducted more large-scale (division and larger) amphibious operations and due to the Pacific, had more continuous experience.


I’m good with that but at this stage of the war they did not have a lot of specialized landing craft yet. I saw that wiki said we had no amphibious ships in 1941. Higgins boats began building in 1942.

Interesting that the Japanese were the first with ramped landing craft.