View Full Version : To what extent did fog assist the evacuation of the BEF from Dukirk?

12-26-2014, 02:30 PM
I am currently seeking primary sources which might explain to what exent fog played a part in the successful evacuation of the BEF from Dunkirk. I would be very grateful if anyone can provide any links regarding primary sources for this topic. I would also appreciate any informed discussion.



Rising Sun*
12-29-2014, 08:58 AM
Had a look at my book on Alan Brooke's diaries but couldn't find any mention of fog in the index or in a quick scan of pages covering Dunkirk, although I might have missed something.

As a former occasional small boat sailor, I'm not sure that fog would have been a major advantage overall to the British.

My very limited experience of sea fogs (assuming Dunkirk was a sea fog) from a potential tactical viewpoint is limited to leaving a nice sunny beach and in the few minutes it took to climb up maybe 40 to 50 metres high of sand dunes a sea fog had formed and completely obscured the beach below us and for a good way out to sea. Very handy for protecting anyone under the fog from air attack, but not so handy for allowing movement of boats and ships as fog pretty much paralyses them as, depending upon the density of the fog, they either can't move or have to move at a painfully slow pace.

I don't know what the wave conditions were like at Dunkirk but, if I was bringing a small boat to shore through even modest waves in a thick fog when I couldn't see more than a few metres, I wouldn't even attempt it without the visual reference of the shore and a good view of the waves in front of and behind me. It takes very little to swamp or broach and capsize a small boat in shore waves. The closer you get to shore, the worse it gets. It would be very difficult to work out where the shore was from seeing waves a few metres away as they don't necessarily break parallel to the shore. Admittedly, my comments are influenced by a surf beach I'm used to where you'd have to be nuts to try to bring a small boat to shore, but in gentler conditions it would be feasible and it's not uncommon in some places for small boats to launch and retrieve from the beach without problems.

Here's what happens when a boat handler tries to ride a wave to shore in good visibility, falls off the back of the wave, gets slowed down in the suction, probably tries to power up while being force surfed bow down by following wave, and duly broaches and capsizes. Okay, it's a bar crossing which can be worse than beaching, but the principle is the same. https://www.youtube.com/watch?v=eaHf3QtXUws Try doing that in fog, when you can't even see the approaching following wave you're going to catch to come to shore.

I suppose it comes down to balancing the fog's ability to frustrate air attacks on the evacuation and stopping observations such as artillery (although off hand I can't recall any German artillery being in range, but I'm happy to be corrected on that) against whatever limitations it put on bringing vessels to loading points for evacuees and moving them back to larger ships or back across the Channel.

In summary, if air attacks were the major threat, then fog preventing air attacks would have been beneficial to the British if that benefit wasn't offset more by reducing the mobility of water vessels carrying evacuees.

01-07-2015, 04:32 AM
The British tried to do most evacuations by night, the large ships coming in at last light and departing at dawn from the Quays - hastily built ones and permanent structures.

This was to minimise the time the ships spent stationary under the bombs.

German artillery was in range of at least the perimeter defences of the Channel Ports (the evacuation was not just from Dunkirk of course), but types and concentrations or ammunition available I have no clue about - most of it being horse drawn and reliant on rail and horse cart resupply.

01-09-2015, 06:31 AM
Just on the subject of the vulnerability of the Channel Ports to German artillery - the Germans did indeed have "siege train" type artillery capable of hitting the Ports. However, it is very unlikely that any of this was available at the French coast at the time of the Dunkirk evacuation. At that time, the Germans were still involved in plugging the holes in their seriously extended flanks by leap-frog advances on the part of motorized infantry and marching infantry units. Heavy artillery units had been left far behind and, indeed, would not have been priority for a rapid move forward. Indeed, this would probably have been impossible due to the reliance of most heavy artillery units on horse power (in the most literal sense). Heavy artillery was assigned to the Normandy area, but only seems to have begun arriving some 2-3 months later than Dunkirk. Even then, the gunners were hampered by chronic ammunition supply difficulties, not to mention the fact that many of these powerful guns were subject to relatively rapid "shooting out" barrel damage, in consequence of which commanders were disinclined to use them other than against very definite targets. As you say, leccy, the Germans had the guns but not, in this case, at the right place, at the right time. Best regards, JR.

01-09-2015, 12:52 PM
I can imagine the German infantry having their organic le.IG 18 75mm Infantry guns but they had a relatively short range. maybe some of the Divisions field guns but not the heavy guns.

With French resistance stiffening and the next phase of the battle for France about to begin, German supply lines were stretched. Units were being re-positioned during the lull to face the new French lines and attempt to resupply, replace losses and give the mobile divisions much needed time for urgent maintenance.

The evacuation from the Channel Ports was not the main factor bothering the German high command - they had advanced faster and further than they thought possible, they could not keep up with the re-supply and the Panzer Divs were largely isolated and in need of time to re-form. The continued fighting and limited counter attacks made elsewhere, memories of the worry and panic caused by the Arras spoiling counter attack.

All this and more affected what was sent where and what units got priority for replenishment, they were not expecting the French to turn round and surrender when they did.

01-14-2015, 09:40 AM
Thank you for the responses, fellas, they sit well with my own thoughts. There are reports of fog, but to what extent it impeded the German operations I can't say. Having read Manstein's and others' memoires I don't think that fog was a major impediment to the Germans. Manstein puts the blame for the German failure to trap and capture the BEF squarely with the German high command, by its insistance on halting the advance on two occassions.

The reasons for the halts have their own myths, not least the one of the power struggle between Hitler and his senior generals for control of German forces. As we know, Hitler may have won that struggle before operatons commenced. Arguably, Hitler's success against his generals can to a large extent be attributed to the sycophantism of Keitel.