It is often claimed that the appearance of the M3 medium tank, the Grant in British service, was a “surprise” to General Rommel as he executed the southern envelopment of the Gazala line at the end of May 1942. See e.g. here, here, here, or here and claims made by Lewin, in Rommel as a Military Commander (“The new American tank was, of course, the Grant: these, with their 75-min. gun, as well as the 6-pounder anti-tank gun, were the technical surprises sprung by the British at Gazala”) and Mitcham in Rommel’s Greatest Victory (“During this battle , Rommel had his first nasty surprise of the campaign . For the first time he met the Grant tank , and found its 75 – millimeter gun was much superior to the 50 – millimeter gun of the PzKw III”) and similar claims made by Ken Ford, Simon Forty, Stephen Sears, and indeed Richard Holmes and Martin Marix Evans.
This is sometimes linked to a statement by Rommel in the ‘Rommel Papers’, where he noted: “Up to May of 1942, our tanks had in general been superior in quality to the corresponding British types. This was now no longer true, at least not to the same extent.” Of course, that in itself does not indicate he wasn’t aware of the existence of the M3 medium tanks, although that is what the Rommel Papers state on p. 206 “There was also a British surprise awaiting us here, one which was not to our advantage—the new Grant tank”. – this is contradicted explicitly in von Mellenthin’s Panzer Battles: “Contrary to a statement in Rommel’s Krieg ohne Hass (p. 130), we did know that the British
were receiving Grant tanks, about which our Intelligence appreciation of 20 May included a full
description.” The document referred to is below.
Grant and Lee tanks of ‘C’ Squadron, 4th (Queen’s Own) Hussars, 2nd Armoured Brigade, El Alamein position, Egypt, 7 July 1942. IWM E14053
The M3 Grant Medium Tank
The M3 medium tank, Grant in British, and Lee in US service, was a stop-gap solution to a serious tactical and engineering problem. It resolved the challenge of putting a 75mm gun into a tank when your industry didn’t yet have the tools to produce a turret big enough to hold it. Sponson-mounted heavy guns were standard in World War I, but kept being designed early in World War II. For example, the French Char B heavy tank featured the arrangement, as did the early version of the British Churchill infantry tank also mounted a 75mm gun in the hull, and the Italian M11/39 medium tank, albeit with a 37mm gun.
Addressing the gun problem in this way enabled the production of a large number of reasonably capable tanks, while US industry tooled up to produce the M4 Sherman tank. While the M3 Medium is often overlooked, it did contribute meaningfully to the success of the Allies in North Africa, and continued to be used in various forms in Italy and North-West Europe, where the chassis continued to provide service as an armoured infantry carrier, and as a self-propelled artillery piece, and to mount searchlights. It also continued to be fought as a main gun tank in the Pacific, where Japanese anti-tank and tank capabilities never rose to the levels of the German forces.
Chrysler tank arsenal. Workers in the huge tank Chrysler arsenal near Detroit, putting the tracks on one of the giant M-3 tanks. These rolling arsenals weigh twenty-eight tons, are capable of speeds over twenty-five miles an hour and are equipped with 75 mm. field artillery gun and a 37 mm. anti-aircraft gun[*], as well as four mounted machine guns and various unmounted arms its crew may carry. The tanks are powered by 400 horsepower Wright Whirlwind aviation engines. Library of Congress
[*]As noted by Peter Brown, despite it being used as such in the movie Sahara, the 37mm was of course not an AA gun.
In the end, the M3 medium tank was a useful stepping stone, and it did deliver much needed additional firepower to the Allied forces on the desert battlefields, evening the technical odds to some extent. These odds had become enormously skewed against the British tank and anti-tank gun technology at the end of the CRUSADER battle. The n, the almost complete annihilation of the 1941 cohort of German tanks in the desert caused better armoured variants to be shipped as replacements, and these in turn caused the standard 2-pdr gun to become obsolete from then on. While British anti-tank regiments continued to be convert to the new 6-pdr guns, which could defeat this armour, no such conversion was forthcoming for the British tanks.
German knowledge prior to Operation Venezia
So what did the Germans know prior to the start of their attack on the Gazala line. We are fortunate enough that much of the documentation of Panzerarmee Afrika has survived, and in these surviving documents the following can be found.
Appendix 1 to High Command of Panzerarmee Africa Ia Nr. 50/42 gKdos Chefs. of 20 May 1942
ENEMY INFORMATION NOTE
IV. Tank State
a) Tank strength see attachment 4.
b) The training state of the armoured formations remains high variable at present. There is an apparent lack of tank gunners and technical personnel. The crew of the American medium tank was therefore reduced from 7 to 6 men.
c) American Tanks
In recent months, light and medium American tanks were added to the British armoured formations in larger numbers. The ratio of English cruisers to American light tanks M3 is about 2:3. Since January the medium American tank M3 “Pilot” was introduced with the armoured formations.
In the English view, the main criticism of the light American tank was the hand-cranked turret. The medium tank M3 “Pilot” should, contrary to British instructions and habits until now, only fire while halted. Fire while moving, at a distance of 3-400m is considered uncertain, and should therefore not be utilized. Tests had shown that the 7.5cm ammunition of the medium American tank was not performing sufficiently to meet requirements. Rounds with fuse M46 ricocheted at firing distances of 700-1,700m without detonating. New fuses were therefore to be developed.
This information, which was gathered from different British sources, allows to conclude at the least that the English do not fully trust the new American tanks, of which the medium is entering combat for the first time.
Attachment 4: British tank strengths in Libya and the Egyptian border region
a) 1st Armoured Division
Staff – 8 cruisers
2nd Armoured Brigade – Staff 10 cruisers,
3 battalions with each
Staff – 4 cruisers
2 companies – 16 cruisers or light American tanks
1 company – 12 medium and 2 light American tanks
Tank battalion – 38 cruisers and 12 medium American tanks
2nd Armoured Brigade therefore as planned: 124 cruisers or light American tanks, 36 medium American tanks, total 160 tanks.
22nd Armoured Brigade, as 2nd Armoured Brigade, 160 tanks.
1st Armoured Division therefore as planned: 256 cruisers or light American tanks, 72 medium American tanks, total 160 tanks.
b) 7th Armoured Division
Staff – 8 cruisers
4th Armoured Brigade – Staff 10 cruisers,
3 battalions with each:
Staff – 4 light American tanks
1 company – 16 light American tanks
2 companies – 12 medium and 2 light American tanks
Tank battalion – 24 light and 24 medium American tanks
4th Armoured Brigade therefore as planned: 82 light American tanks, 72 medium American tanks, total 160 tanks.
22nd Armoured Brigade, as 2nd Armoured Brigade, 160 tanks.
7th Armoured Division therefore as planned: 90 light American tanks, 72 medium American tanks, total 162 tanks.
e) The planned tank state of the armoured formations in Libya and the Egyptian border region is therefore at maximum limit:
– Cruisers and light American tanks: 452
– Medium American tanks: 144
– Infantry tanks: 150
– Total: 746
Based on this document it is clear that the Axis command expected the presence of 144 M3 Medium tanks, equipped with 75mm guns. They had less clarity on the performance of the gun, as the document is not written in a way that allows a conclusion for the reader as to whether the fuse problem had been resolved. It is also not clear whether the fuse problem affected all rounds, or only high-explosive rounds. As such, it is possible that the Axis command underestimated the performance of the tank, and that any surprise relates to this. This interpretation could be also explain a statement in the Battle Report produced by the staff of Panzerarmee, according to which “the medium American tanks M.III. “Pilot” which were used for the first time, proved highly able to resist” (“sehr widerstandsfähig).
A few days later, in the files of 15. Panzerdivision, detailed technical data is presented, which shows that there was very little surprise possible also in regards to the technical specifications.
Appendix 14, 23 May 1942
15. Panzerdivision, Ic
Re: Enemy tanks
Attached an information sheet about the characteristics of the American light and heavy tanks M3, with a side view of the heavy M3 “Pilot”.
When reporting about destroyed or captured American tanks, utmost precision in regards to the naming of the individual cruiser or I-tanks is requested. The tank types are contained in the handbook British Army as well as in the specially issued information sheets.
I – Tank Mark II, IIA, IIAx
I – Tank Mark III, IIIx, IIIxx
Cruiser tank Mark IV, IVa, V, VI, VIa
For the divisional command
The first General Staff Officer
Translation of captured papers
Re: Information about American tank types (preliminary information, subject to change)
Preliminary information about the American light and medium tanks M3 has been received. The data provided below are subject to change based on practical experience made in this theatre. The ammunition carried may also change.
M3 Medium Tank
Weight: 25 tons (27 tons)
2.82m (including turret) (2.72m)
Engine: Wright Whirlwind R975 (same)
Crew: 6 (same)
Front 57mm (50mm, max 56mm)
Sides and rear: 38mm (25-50mm, 38mm sides)
1 – 75mm Browning (75mm M2)
2 fixed .30 Browning operated by the driver
1 – 37mm gun (jointly in turret) (37mm M5)
1 – .30 Browning MG (jointly in turret)
2 frontal MG
1 MG for air defense in turret
1 – 5cm smoke launcher
50 rounds 75mm (46)
150 rounds 37mm Browning (178)
8,000 rounds .30 Browning
1,200 rounds (9,200 rounds for all MGs)
30 rounds 5cm smoke thrower
Gear: automatic (hydraulic/electric)
Radio set: 24/19
Communication inside tank: phone
Fuel carried: 637l
Road: 48 km/h (42 km/h)
Cross-country 19.2km/h (26 km/h)
Terrain-crossing capability: unknown
Hull clearance: 43cm
7 – Protektoscopes (7)
2 – Periscopes, one for the driver, one for the commander (2)
2 – Periscope visors
The side view drawing is unfortunately not included in the file.
When all is said and done, a weapon is only ever as good as the person or commands wielding it. While, tank-for-tank, the M3 Grant presented a serious challenge to the Axis commanders, this was mitigated by the continuing incompetence in British command echelons, which seemed to be incapable of handling a numerically and technologically inferior opponent. Hundreds of Grants were lost in late spring and early summer 1942, and Eighth Army came close to collapse and had to rescue itself by fleeing the battlefield.
WESTERN DESERT, EGYPT. 1942-09-16. GENERAL GRANT M3 MEDIUM TANK KNOCKED OUT. THE CREW WERE BADLY BURNT BUT NONE DIED. AWM024984
 BA-MA RH19-VIII 245
 The attack order for Operation VENEZIA.
 British code name for the M3 Medium, according to Peter Brown’s comment below adopted because the Germans got hold of a prototype picture with the word “Pilot” overprinted.
 Possibly the intercepted notes from Col. Bonner Fellers, Rommel’s ‘Good Source’ – see here for background, and here for reports on the performance of the M3 light tank, the ’Stuart’.
 NARA T315R665, File 24442 Ic Tätigkeitsbericht May 1942
 The Ic position was the staff intelligence officer
 Two of the types did not appear in combat, the cruiser M. BV (Covenanter) and the American M2A4, even though both were present in North Africa in small numbers
 Numbers in brackets based on https://www.ww2-weapons.com/m3-lee-grant/ .
US Army Official History: The Ordnance Department
British M3, M3A2, M3A3 and M3A5 Grants