Ram Mark II manual

[Lauren Child]

I doubt it will list armour values - the service instruction books are more focussed on maintenance and repair.

[Lauren Child]

The data book does though - this may help.

and dimensions

[Matthew Noonan]

Thanks Lauren


Interesting... Values are all over the place depending on source. The top armour values from some sources are confusing, 76.2mm is extremely thick for a hull roof, unless they are counting the curving hull top in front of the turret, areas around the cupola etc and they are the higher values.

Examples

Hunnicutt

Hull
Upper front 76.2 - 50.8
Lower front 50.8
Sides 63.5 - 31.75
Rear 38.1
Top 25.4
Floor 25.4 - 12.7
cupola ?

Turret
Front 76.2
Sides 76.2 - 63.5
Rear 63.5
Top 25.4
Radio floor ?


AFV weapon profile #13

Hull
Front 44.45
Nose 38.1
Sides 63.5 - 31.75
Rear 38.1
Top 76.2 - 38.1
Floor 25.4
cupola ?

Turret
Front 88.9
Sides 63.5
Rear 38.1
Top 38.1
Radio floor ?


Bellona Military vehicle print no. 14

Hull
Glacis plate 50.8
Drivers plate 50.8
Nose upper 76.2 - 50.8
Nose lower 50.8
Sides upper 63.5
Sides lower 38.1
Rear 38.1
Top 38.1 - 25.4
Floor 25.4
cupola ?

Turret
Front 76.2
Sides 76.2 - 63.5
Rear ?
Top ?
Radio floor ?


Canada's pride

Turret
Front 76.2
Sides 76.2 - 63.5
Rear 63.5
Top 25.4
Radio floor?

Hull
Front upper 76.2
Front lower 50.8
Sides 63.5 - 31.75
Rear 38.1
Top 38.1 - 25.4
Floor 25.4 - 12.7
Cupola (no value given one paragraph mentions "thicker then M3, the M3 cupola was roughly 2 inches as far as I know")

Ram MK I for example from the archives and some weights (MK II has the same values other then weight)

http://i.imgur.com/WmO1AFp.jpg

http://i.imgur.com/8jXfvEo.jpg

[Grant Bowker]

Images from the original listing of the book for sale as they will likely eventually disappear with the book sold...

Tank Cruiser Ram II Instruction Book April 1943.
4to., Stiff cloth with folding flaps and snaps, 143pp. Also included inside the front flap is the Canadian Army Training Pamphlet No. 12 Canadian Armoured Corps Crew Drill And Inspection Duties Ram I-II, 1942 and A folding "Gunnery And Ammunition Stowage Diagrams for Ram II Tank" plus a booklet "Ram II Crew Maintenance" and a "Lubrication Chart." Fine.

A scarce collection of original manuals, and diagrams for the Ram Tank, which was designed and built in Canada during the Second World War. The tank was used exclusively for training purposes and never used in combat due to standardization on the Sherman tank.

SOLD

[Grant Bowker]

... I hope the seller doesn't mind.

[45jim]

You are creating a problem by converting from Imperial to Metric. If you are trying to determine the correct thickness of armour plate you need to remember the different methods of production and the inherent tolerance related to each. Only then can you convert. RHA (rolled homogeneous armour) has a much tighter tolerance than cast sections or face hardened plate. I believe you must select the correct source (original manuals) and then examine the relevant specification on manufacture. A common modern material MIL-A-46100 has a nice standard and is widely available and will demonstrate the methodology used in armour production and grading. It shows the variability in dimension and composition that was acceptable. Is this for wargaming?

[Matthew Noonan]

Originally Posted by 45jim

You are creating a problem by converting from Imperial to Metric. If you are trying to determine the correct thickness of armour plate you need to remember the different methods of production and the inherent tolerance related to each. Only then can you convert. RHA (rolled homogeneous armour) has a much tighter tolerance than cast sections or face hardened plate. I believe you must select the correct source (original manuals) and then examine the relevant specification on manufacture. A common modern material MIL-A-46100 has a nice standard and is widely available and will demonstrate the methodology used in armour production and grading. It shows the variability in dimension and composition that was acceptable. Is this for wargaming?

Tolerance thickness varied by date or nation, no idea what Canada was using. 0-5% is a good rule of thumb. With cast in the states I have seen spec sheets that will call for say 2 inches total thickness on a section, but then they will sate "equivalent to RHA plate" so they wanted cast armour that would act the same as if it was 2 inches of RHA, so slightly more then 2 inches in terms of cast armour total.

The spec sheet seems to be the most reliable unless someone in the future finds late manufacturers drawing plans, but was the tank constructed using an armour basis curve? it does not say, so again more confusion.

And if it is using a armour basis curve, what nations? the US? British? or did Canada have it's own? They evolved over time as well.

Example of a US curve from 1943.

http://i.imgur.com/IPU5D3F.jpg

Brig. Worthington had this to say in the summer of 1941 after talking to the British.

On cast armour

"In discussing plate thickness the opinion given was that working on a basic thickness for upright surfaces and then thinning down on the slopes was definitely bad practice. It was felt the sloping surfaces of a tank will be very often presented to normal impact and that therefore to depend on thin plates due to slope is asking for trouble. Whereas in the case of upright sides the resistance to normal impact is known at any angle beyond normal impact, the resisting power of the plate will simply be increased."

"I discussed the question of streamlining the top cast hull as on the Canadian M3 Cruiser. Opinions rendered indicate that so long as the basic thickness was maintained up to the gentler slopes, it could be thinned down with immunity where the surface is more horizontal. This point should be looked into"