M4 versions

So you're saying they were already across the Atlantic in Britain and they were lost after they were shipped from England? So there were no M4 losses in the Battle of the Atlantic?

 

No. Once the British purchased a tank via cash and carry or Lend-Lease, it was "theirs". They did not take ownership once the tanks arrived in England. Many of those British "at sea" losses were due to the Battle of the Atlantic, but many were not. However, they were all lost "at sea".

Crap! Just noticed I missed listing the Lee/Grants and Chaffees lost at sea. It was 22 Lees, 168 Grants, and 8 Chaffees. Sorry. Not sure how the Chaffees got lost at sea since so few (289) went to the British.

 

So the Battle of the Atlantic really didn't affect the number of tanks that were shipped from America...

I'm guessing war planes that were shipped by sea weren't that affected either?

 

Um, 1.4% to 12.0% loss is kind of an "affect". Whether the effect was on tanks or planes or anything else.

 

Maybe designed badly, but at least they showed, that the idea sloping armor wasn't unknown to british engineers. Anyone can explain, why the later, successful tanks (Cromwell, Churchill) were designed like boxes on tracks again?

 

Of course it wasn't unknown, to British or any other designer. Which is why the specification called for an armor basis of 1 1/4 inches...the flat driver's faceplate was that thick, the sloped hull front was less so. That caused problems when the armor basis in the front was increased to 1 5/8 inches. Otherwise, the turret front was flat, the hull sides were flat, and only the turret sides were angled - the inward sloped lower side and rear making a nice shot trap. In reality, Cromwell and Churchill were much better armored, sloped or not.

Then of course there are the problems with sloped armor. Like smaller interior volume. Smaller upper hull areas - a real problem when the Soviets tried to improve the turret in the T34. The Christie suspension also created a problem, since it also consumed interior volume. That is why the Covenantor radiators were in the front and the engine in the rear - not enough room to put them together, especially given the flat, wide engine layout.

 

It is interesting to me that the British produced a tank near the war's end, the Centurion, that proved itself to be one of the world's best, some say the best,, MBT for the decades after the war. A modified one was Israel's MBT of choice in the Six Day's and 73 wars.

 

Was the 105mm M4 available for the Normandy invasion or did it come in with the follow-up troops for the breakout? Also, since it was a short-barreled 105mm howitzer, it wasn't suitable to tank on other tanks, correct?

 

No, the first M4 (105mm) were accepted in February 1944 and the first M4A3 (105mm) in May 1944. Approximately 160 were shipped to the ETOUSA between 1 June and 31 August 1944, with the first issued to the 4th and 6th AD, and the Separate Tank Battalions in early July. The 105mm howitzer HEAT round could be quite effective and was one of the few which could be expected to penetrate the front glacis of a Panther (one lost at Mortain was likely to an M3 105mm Howitzer of one of the Infantry Cannon companies).

 

How did the Allies disable Panthers otherwise? Aiming at the sides? By aircraft?
Panthers were not rare any more in late 1944.

 

What was the assault gun used for the Normandy invasion if the fist M4 105s weren't available until later in the campaign? I thought Howitzer's weren't as powerful as a regular canon, especially since its shorter, but it was effective against the front of a Panther?

 

All the separate battalions prepared for the assault under a modified TO&E. The personnel of the Assault Gun Platoon and Sections in the battalions were utilized to man additional 75mm-armed M4 and M4A1 drawn from the ETO tank reserve. In April and May a crash program mounted many of them with the newly developed dozer blade kit, producing the first Tankdozers (a total of about 60, another 40 were allocated to British use). Each of the three assault battalions had six tankdozers manned by the assault gun crews and another two manned by hastily trained crews from the Engineer Light Equipment companies of the three Engineer Groups assigned to the assault.

HEAT = High Explosive Anti-Tank. It utilizes the so-called Monroe shaped-charge effect to generate armor penetration. The only problem in using it from howitzers was the greater dispersion of the howitzer in direct fire as opposed to a gun.

BTW, in the U.S. Army Field Artillery lexicon, a "cannon" is simply the tube down which the projectile is fired. Both howitzers and guns are cannon, but a howitzer is not a gun and a gun is not a howitzer.

 

That's what I meant, that a howitzer was not as powerful as a gun of similar caliber and length.

Was that M7 "Priest" gun on the Sherman Chassis effective against tanks?

So before the M4 105mm became available, additional 75mm M4s were used as "assault guns" or did I misread your post?

 

A howitzer is designed to do a different job to a gun. Howitzers lob high explosive shells in a looping trajectory at a lower velocity than a gun which fires shot or shell at a higher velocity in a flatter trajectory. Guns are good at punching armoured shot at tanks (or shells to intercept aircraft.)

The M4 had a very useful 75mm HE round weighing 6.76 kg (14.9 lb). This was the main ammunition used by M4 shermans whose main targets were infantry and emplacements rather than tanks. However, the same recoil system could support a 105mm Howitzer firing a 14.97kg 35 lb HE or WP smoke round. This was a lot more effective against fortifications, dug in infantry or em-placed equipment, which is why it was supplied in small numbers to armoured and armoured infantry units to provide close support in a direct or semi indirect role. It was not intended to fight tanks. The 105mm M7 SP Howitzer was very similar ordnance firing the same ammunition. It was intended as a field artillery equipment delivering fire in an indirect or semi indirect role.

A 105mm HE round would not have much effect in a 45 ton tank. A 105mm HEAT round was designed for anti tank use. HEAT works by using the Monroe effect to create a jet of molten metal which could burn a hole in the armour of a WW2 tank. This is more effective from a non rotating projectile such as a bazooka than from a howitzer because the spin of a round from a rifled howitzer can disperse the jet.

 

But could it take on a tank if it came down to it or if it had a chance at a clean shot?

 

Yes it could. However it was not designed with that role in mind. One of the problems with the early makeshift models supplied in '44 was that the 105mm gun was out of balance. This resulted in the power traverse not working on slopes. When this was discovered during initial testing they decided not to install power traverse in the turrets. This allowed more rounds of ammunition to be stored and was not seen by the designers as too much of a problem as the targets it was intended for were infantry and bunkers.

However in tank vs tank combat power traverse in extremely helpful in getting your shot off first.

 

Sorry, but no. A howitzer "of similar caliber and length" to a gun is a gun, it isn't a howitzer at all.

The "gun" on that M7 "Priest" wasn't a "gun", it was a howitzer. Again, you are mixing two different things. Yes, firing HEAT it could be very effective against tanks. The problem was the howitzer was not designed for direct lay engaging mobile targets like tanks. It was hitting them that was the problem.

No, the personnel in the organizations nominally meant to man the M4 105mm assault guns were used to man additional 75mm-armed M4 tanks in the assault.

 

Sorry, but you are mixing two different things. The problem with turret traverse on slopes was found in the early attempts to mount the 76mm Gun in the Medium Tank M4. In 1942, not 1944.

The M4 105mm were not "makeshift models" and had no problem with the 105mm being out of balance or in traversing on a slope. It was decided early on that the power traverse was unnecessary for their role, which was found to be a mistake in practice. Insofar as i have found though the decision was not made because of ammunition worries - the traverse mechanism did not take up that much space which could be used for ammo.

 

Yes, with a HEAT round which had a penetration of just over 100mm of armour https://en.wikipedia.org/wiki/M101_howitzer

The HE round would not have that much effect on a late war tank. I sat in a Centurion tank, part of a mixed group of chieftain and centurions subject to fire from 105mm guns using more modern post war ammunition. One tank received a direct hit on the upper surface with no adverse effects. (though the tanks suffered $500k in damage to external fittings such as vision blocks and radio aerials etc.

 

Books on the subject also mix up terms then. In a World War II book I have, they describe the 155mm "Long Tom" canon as both a gun and a howitzer. Its a long barrel, and that length could be used on a gun or a howitzer, which is why I compared a gun or howitzer of similar length.