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— CH. 1 · SIGNALS AND THE SILENT WAR —

Operation Crusader

~7 min read · Ch. 1 of 7
7 sections

  • In August 1941, a German signals unit known as FAK 621 began reading British tactical codes with startling accuracy. This intelligence stream continued through January 1942 and provided Erwin Rommel with high-quality information about enemy movements. The Germans exploited British incompetence in using radio telegraphy without encryption and an ineffective call-sign procedure that moved from brigade to battalion levels. Wireless traffic flowing from the Eighth Army headquarters down to divisional commands was intercepted and decoded by the Germans. Until January 1942, when the British improved their recyphering methods, the Germans obtained as much data on the British order of battle as Ultra decrypts revealed about Axis forces. In October 1941, British Enigma decrypts contained German data showing increased tank strengths within British units. The War Office became seriously worried about signals security but did not learn the full extent of German eavesdropping until July 1942 when they captured FAK 621.

  • A single German motorised division required thirty tons of fuel per day and needed hundreds of lorries to move supplies across the desert. With seven Axis divisions plus air and naval units, the force needed thousands of tons of supplies each month. The Vichy French allowed Germany to use the port city of Bizerta, yet no supplies reached there until late 1942. From February to May 1941, a surplus of five thousand tons arrived, but attacks from Malta sank ships at alarming rates. In May, the worst month for ship losses, ninety-one percent of supplies still made it through. Lack of transport in Libya left German supplies stranded in Tripoli while Italian forces had only two hundred trucks to move goods. A record amount of supplies arrived in June, but shortages worsened at the front. Road transport consumed thirty to fifty percent of all fuel deliveries, and thirty-five percent of supply lorries were unserviceable. During Operation Crusader, a five-ship convoy was sunk and air attacks on road convoys prevented daylight journeys. British ambushes destroyed about half of the remaining Axis transport as they retreated toward El Agheila from four December.

  • Tobruk served as a vital harbor for supplies, making its control essential for both sides. Winston Churchill and the British War Cabinet demanded that General Archibald Wavell prevent its loss despite repeated Axis attempts to capture it. The garrison consisted mainly of the 9th Australian Division who defeated an Axis attack in May 1941. They settled into active defense by patrolling most nights and reconnoitering enemy positions. Larger sorties required reinforcements from Egypt which were not available. The 20th Australian Infantry Brigade improved their position at the Ras el Medauar salient while the 24th Australian Infantry Brigade made an abortive attack on the shoulders of the salient. The garrison returned to active defense after these failed efforts. On the 21st of November, the 70th Infantry Division planned to break out from Tobruk and cut off German forces to the southeast. The night before, the garrison gapped the wire, planted minefields, and placed four bridges over the anti-tank ditch. Fourteen infantry brigades moved up with detachments of field companies and armored cars designed to lift mines.

  • Before dawn on the 18th of November, the Eighth Army advanced westwards from Mersa Matruh and crossed the Libyan border near Fort Maddalena. Storms grounded aircraft of both sides that night. The 7th Armoured Brigade advanced northwest toward Tobruk while the 22nd Armored Brigade moved west. To the west, the 22nd Armored Brigade met the Ariete Division at Bir el Gubi. After a sharp action they withdrew after twenty-five new Crusader tanks were knocked out for an Italian loss of thirty-four tanks. In the center, the 7th Armored Brigade and Support Group advanced to Sidi Rezegh airfield capturing nineteen aircraft. They menaced the rear of Axis defenses but dug in facing south after counter-attacks failed. To the east, a battlegroup of the 21st Panzer Division moved to Gabr Saleh and knocked out twenty-three Stuart tanks of the 4th Armored Brigade by nightfall. By attaching the 4th Armored Brigade to XIII Corps, General Cunningham allowed British tanks to become dispersed before meeting main Axis forces. On the 23rd of November, the 5th South African Brigade was destroyed at Sidi Rezegh yet caused many German tank losses. From 18 to the 22nd of November, the dispersal of British armored units led to them suffering five hundred thirty tank losses against about one hundred Axis losses.

  • Later on the 23rd of November Rommel decided to finish off the 7th Armored Division and advance toward Sidi Omar. He took command of the Afrika Korps and Ariete Division to destroy remnants of the British force. The German and Italian tanks scattered many rear echelon support units in their path. They split XXX Corps and almost cut off XIII Corps from Egypt. On the 25th of November, the 15th Panzer Division set off northeast for Sidi Azeiz but found the area empty. It was constantly attacked by Desert Air Force bombers south of the border. Panzer Regiment 5 attacked the 7th Indian Brigade at Sidi Omar but was repulsed by field artillery firing over open sights. A second attack left Panzer Regiment 5 with few operational tanks. By evening of the 25th of November, the 15th Panzer Division was west of Sidi Azeiz down to fifty-three tanks. The Axis column had only a tenuous link to supply dumps on the coast between Bardia and Tobruk. Supply convoys had to find ways past New Zealand Infantry Brigades. On the 26th of November, the 15th Panzer Division bypassed Sidi Azeiz heading for Bardia for supplies. The remains of the 21st Panzer Division attacked northwest of Halfaya toward Capuzzo and Bardia.

  • On the 23rd of November, the 70th Infantry Division in Tobruk attacked the 25th Bologna Infantry Division to reach Sidi Rezegh. Parts of the Pavia Division arrived and contained the attack. The 7th Armored Division planned its attack northward to start at dawn on the 21st of November but patrols reported tanks to the southeast. The 7th Hussars and 2nd Royal Tank Regiment faced tanks while four infantry companies with Support Group guns attacked north. Expecting reinforcements from the 5th South African Infantry Brigade, the South Africans were detached from Bir el Gubi en route. The Support Group attack failed and by nightfall the 7th Armored Brigade held on with only twenty-eight runners remaining. The South African brigade was dug in southeast of Bir el Haiad but panzers stood between them and Sidi Rezegh. By dusk on the 21st of November, the 4th Armored Brigade was south-east of Sidi Rezegh while the 22nd Armored Brigade contacted German tanks at Bir el Haiad. On the 22nd of November, the 21st Panzer Division attacked Sidi Rezegh and captured the airfield despite having fewer tanks. German all-arms tactics knocked out fifty tanks mainly from the 22nd Armored Brigade and pushed the 7th Armored Division back.

  • On the 7th of December, Rommel decided to narrow his front and shorten lines of communication by abandoning Tobruk. He withdrew to positions at Gazala which had been prepared by Italian rear echelon units and occupied by eight December. The weakened Italian Mobile Corps anchored the southern end of the line at Alem Hamza while the Afrika Korps waited behind the southern flank ready to counterattack. On the 6th of December, Rommel ordered his divisions to retreat westward. On the 8th of December, OKW ordered Italian and German garrisons at Sollum, Halfaya and Bardia to resist as long as possible. Bardia surrendered on the 2nd of January 1942 and on the 17th of January Axis troops around Halfaya Pass capitulated. For ten days, Axis forces withdrew to a line between Ajedabia and El Haseia maintaining supply lines. As lines shortened and deliveries improved, Rommel rebuilt tank forces while Eighth Army lines lengthened. On the 27th of December, during a three-day tank battle at El Haseia, the 22nd Armored Brigade was severely depleted forcing vanguard withdrawal. Axis forces fell back to better defensive lines at El Agheila in early January.

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Battle of Alam el HalfaBattle of GazalaOperation CompassFirst Battle of El Alamein

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Common questions

When did the German signals unit FAK 621 begin reading British tactical codes during Operation Crusader?

The German signals unit known as FAK 621 began reading British tactical codes in August 1941. This intelligence stream continued through January 1942 and provided Erwin Rommel with high-quality information about enemy movements.

How many tons of fuel did a single German motorised division require per day during Operation Crusader?

A single German motorised division required thirty tons of fuel per day during Operation Crusader. The force needed hundreds of lorries to move supplies across the desert while road transport consumed thirty to fifty percent of all fuel deliveries.

Which Australian Division defended Tobruk against Axis attacks in May 1941?

The garrison at Tobruk consisted mainly of the 9th Australian Division who defeated an Axis attack in May 1941. They settled into active defense by patrolling most nights and reconnoitering enemy positions.

What happened to the 7th Armored Brigade on the 18th of November during Operation Crusader?

Before dawn on the 18th of November, the 7th Armored Brigade advanced northwest toward Tobruk while the 22nd Armored Brigade moved west. The 22nd Armored Brigade met the Ariete Division at Bir el Gubi after which twenty-five new Crusader tanks were knocked out for an Italian loss of thirty-four tanks.

When did Rommel decide to abandon Tobruk and withdraw to Gazala during Operation Crusader?

On the 7th of December, Rommel decided to narrow his front and shorten lines of communication by abandoning Tobruk. He withdrew to positions at Gazala which had been prepared by Italian rear echelon units and occupied by eight December.

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All sources

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