D-Day naval deceptions
| Taxable, Glimmer and Big Drum | |
|---|---|
| Part of Operation Bodyguard | |
 A Harbour Defence Motor Launch, similar to those used during the operations | |
| Operational scope | Tactical Deception |
| Location | English Channel |
| Planned | 1944 |
| Planned by | London Controlling Section, Ops (B) |
| Target | Cap d'Antifer, Pas de Calais, Normandy |
| Date | 5–6 June 1944 02:00 – 06:00 |
| Executed by | No. 617 "Dam Busters" Squadron Royal Naval Reserve |
| Outcome | Limited success in deceiving the enemy as to Allied intentions. |
Operations Taxable, Glimmer and Big Drum were Allied naval deceptions carried out in support of Operation Neptune, the Allied landings in Normandy, on 6 June 1944. They formed the naval portion of an overall tactical strategy associated with the landings (complementing an airborne component, Operation Titanic) under the wider, strategic, Operation Bodyguard deception.
The operations took the form of small boats and aircraft from RAF Bomber Command simulating invasion fleets (using chaff, radar jamming, decoys and wireless traffic) approaching Cap d'Antifer, Pas de Calais and Normandy. Glimmer and Taxable played on the German belief, built up by the Operation Bodyguard plan over preceding months, that the main Allied invasion force would land in the Calais region. Big Drum was positioned on the western flank of the real invasion force to try and confuse German forces about the scale of the landings.
It is unclear whether the operations were successful, due to the complexity of their execution, bad conditions and lack of response from German forces. It is possible they contributed to the overall confusion of D-Day as part of the wider Bodyguard plan.
Background
Glimmer, Taxable and Big Drum were conducted as part of Operation Bodyguard, a broad strategic military deception intended to confuse the Axis high command as to Allied intentions during the lead-up to the Normandy landings. The London Controlling Section had spent some time convincing German high command that the First United States Army Group (FUSAG) represented the bulk of the Allied invasion force. FUSAG, however, was entirely fictional – its existence fabricated through Operation Fortitude South.[1]
The Allied "story" for FUSAG was that the army group, based in south-east England, would invade the Pas de Calais region, probably several weeks after a smaller diversionary landing in Normandy. As D-Day approached, the London Controlling Section moved on to planning tactical deceptions to help cover the progress of the real invasion forces.[2] As well as naval operations, the LCS also planned operations involving paratroopers and ground deceptions. The latter would come into effect once landings were made, but the former (involving naval, air and special forces units) were used to cover the approach of the true invasion fleet.[3]
In preparation for the coming landings, Allied scientists had worked on a number of techniques for obscuring the size and disposition of an invasion force. For example, radar jamming using wireless sets and WINDOW (chaff). Allied command decided that this would be too noisy, alerting the Germans to an approaching fleet. Instead it was decided to combine these techniques with small groups of boats to simulate an entire invasion fleet aimed at the Calais region – Operations Taxable and Glimmer. The chaff and other countermeasures would hide the small size of the naval force, and wireless traffic would mislead the Germans into expecting a large invasion fleet.[4]
It was also decided that another deceptive force would use radar counter measures on the western flank of the true invasion fleet. Operation Big Drum was intended to lend confusion as to the true extent of the landings in Normandy.[4]
Glimmer and Taxable
Glimmer and Taxable were very similar operations. They were executed in the early hours of June 6 1944, whilst the true invasion fleet was approaching Normandy. Taxable simulated an invasion force approaching Cap d'Antifer whilst Glimmer threatened Pas de Calais. By dropping WINDOW (chaff) in progressive patterns, Royal Air Force bombers were able to create the illusion of a large fleet on coastal radar screens. Beneath the chaff small boats towed radar reflector balloons and simulated the radio traffic expected of the larger force.[4] If successful in drawing German forces toward the coast, RAF bombing raids would target bridges and roads to keep the armies away from Normandy.[5]
The operations required precise accurate flying, in elongated circuits, with replacement aircraft having to merge in seamlessly avoid tell tale gaps.[6] The bombers were staged at two mile intervals parallel to the French coast; they would spend two and a half minutes flying toward the coast, dropping chaff at 15 second intervals, before turning and heading away from the coast for two minutes and ten seconds. By repeating this circuit the wide cloud of chaff edged toward the coast just like a real sea-borne fleet.[5] The aircraft had to be modified by cutting a hole in the nose to allow the large quantities of chaff to be dropped.[7]
Taxable, the larger of the two, was carried out by eighteen ships, a mix of Harbour Defence Motor Launches (HDML) and Search and Rescue Pinnaces, designated Special Task Force A.[6][8] Chaff was dropped by Lancaster bombers from the famous No. 617 "Dam Busters" Squadron, with an expanded crew of up to 14. The squadron began training for the operation as early as May 7, but were not aware of the final target or intention.[5][3]
Task Force A struggled in bad seas, affecting their equipment and ability to converge at their meeting point. However by 00:37, on schedule, the lead boats had reached the muster point and headed toward the French coast. Between 02:00 and 04:00 the ships operated radar and radio equipment as they headed toward a point 7 miles offshore. From there the task force simulated a landing attempt, by running fast to within two miles of the beach, before returning to the 7 mile marker under cover of smoke. During this time only a small German response was observed – searchlights and intermittent gunfire. Shortly after 5am the operation ended, and the task force laid mines before heading toward Newhaven, reaching it by mid day.[6]
The air operations for Glimmer were conducted by No. 218 "Gold Coast" Squadron, flying Short Stirling bombers. The squadron was much smaller than No. 617 and so no relief aircraft were available, instead each bomber carried a second pilot who rotated flying. The naval contingent, Special Task Force B, consisted of 12 HDMLs, again equipped with jamming gear, radios and balloons. They began jamming operations at shortly after 1am followed by radio chatter around an hour later.[9]
Glimmer elicited more response from German forces, including reconnaissance planes sent to investigate the "fleet". After completing their assignment (which, unlike Taxable, did not include laying mines) the small ships returned to port, reaching their berths by 13:00 on D-Day.[9]
Big Drum
Big Drum was similar to the other D-Day naval deceptions, however was not supported by chaff-dropping bombers. Instead Task Force C consisted of four HDMLs whose job was to operate as a distraction on the western flank of the invasion. Attached to "U" convoy (the western most portion of the fleet). The plan originally called for the task force to operate radar jamming equipment as it approached the French coast, holding 2 miles off shore until first light. However, as the Germans failed to respond the ships edged closer, to within 1 1/2 miles of the coast.[10]
Impact
The extent to which Taxable and Glimmer were successful has been debated. All three operations were complicated in execution, requiring the coordination of air and naval forces in poor conditions. Bad weather conditions made Taxable quite ineffective, very little enemy response was observed during the operation. The reaction to Glimmer was more encouraging. The attacks on the bomber squadrons indicating, at least to the satisfaction of Bomber Command, that the Germans believed a genuine threat existed. There is no evidence that Big Drum elicited any specific response from the shore. All of these factors contributed to making the operations less effective than the planners might have envisioned.[9]
Although disappointed not to have seen any "action" during the night of D-Day, and still unclear what impact they had had, the bomber crews felt proud of the operations. Squadron leader Les Munro, of No. 617 Squadron, wrote, "I have always considered the operation in one sense to be the most important the squadron carried out in my time - not because bad weather, nor because of any threat of enemy action and not measured by any visible results, but because of the very exacting requirements to which we had to fly and navigate".[11]
From intelligence intercepts it appears that German forces in the Pas de Calais region reported an invasion fleet, and there are reports of the decoys being fired on by shore batteries. In a 11 June report on the operations, Lieutenant Commander Ian Cox (who was in charge of deception units) indicated that German forces had been convinced by the fake radio traffic.[6] Intercepted dispatches from Hiroshi Ōshima, the Japanese ambassador to Germany, made reference to the naval deceptions. A June 8 report referred to the Calais region and stated "an enemy squadron that had been operating there has now withdrawn".[3]
References
- ^ Latimer 2001, pg. 218–232
- ^ Latimer (2001), pg. 232–234
- ^ a b c Holt (2004), pg. 578–579
- ^ a b c Barbier (2007), pg. 70–71
- ^ a b c Bateman (2009), pg. 68
- ^ a b c d Barbier (2007), pg. 108–109
- ^ Levine (2011), pg. 269
- ^ Brickhill (1977), pg. 207–208
- ^ a b c Barbier (2007), pg. 110–111
- ^ Barbier (2007), pg. 111–112
- ^ Wilson (2008), pg. 362
Bibliography
- Barbier, Mary (2007). D-Day Deception: Operation Fortitude and the Normandy Invasion. Greenwood Publishing Group. p. 268. ISBN 0275994791.
- Bateman, Alex (2009). No. 617 'Dambusters' Sqn. Osprey Publishing. ISBN 1846034299.
- Brickhill, Paul (1977). The Dam Busters. Evans Bros. p. 238. ISBN 0-237-44886-6.
- Holt, Thaddeus (2004). The Deceivers: Allied Military Deception in the Second World War. Scribner. p. 1168. ISBN 0743250427.
- Latimer, Jon (2001). Deception in War. New York: Overlook Press. ISBN 978-1-58567-381-0.
- Levine, Joshua (2011). Operation Fortitude: The True Story of the Key Spy Operation of WWII That Saved D-Day. HarperCollins UK. ISBN 0007413246.
- Wilson, Kevin (2008). Men Of Air: The Doomed Youth Of Bomber Command. Hachette UK. ISBN 0297857045.
Further reading
- Beevor, Anthony (28 May 2009). The Battle for Normandy. Penguin UK. ISBN 0141959266.