3" S.P. RAM Mk. I

Thatz · June 10, 2023

Description:

The 3" S.P. RAM Mk. I was in a basic sense was a M10 turret mounted onto a Ram chassis. Basically Canada's attempt at an M10.

In May 1942 orders were released from Canada and Britain to create a "First-rate Tank Buster". The Canadian Director of Artillery tried to work with the Department of Munitions and Supply and the Canadian Army Staff that were in Washington D.C. to receive a prototype example of the M10 so it could be tested for possibly be adopted to fit the request role for Canada.

In June 1942 the M10 prototype (T54E1) was approved by the US Ordnance Department and entered production under the name M10 in September 1942. U.S. Ordnance Department had agreed to supply Canada with examples of the M10 but at the time of Canada's request there were new production vehicles that were available until September or later. Since vehicles weren't available for Canada the U.S. Ordnance Department suggested to the Canadian Director of Artillery that they build their pilot model of the M10 on a Ram chassis and US would loan the gun, turret and turret ring from one of the prototype models of the M10 (T54E1), they also provided the drawing of the M10. The Master General of the Ordnance agreed to set aside a Ram chassis for this conversion however some modifications were required to be made to make the conversion work: adding in an armoured plate to support the turret, and modifying the engine hatch as the M10 has a diesel engine but the Ram tank uses a radial engine. The T35E1 turret arrived in Canada on August 28th 1942 and the drawings for the M10 were received on August 29th 1942.

On September 3rd 1942 the Army Technical Development Board approved the project under the name Project 35 and tasked the development of a pilot model to Montreal Locomotive Works with an estimated cost of 75,000$. The Canadian Department of Munitions and Supply did not think that the project would go anywhere as they were putting the Sexton, the Ram 3.7in S.P. (the QF 3.7 Ram found in game (however the in-game name is incorrect)) and the changing of production from Ram tanks to Grizzlies as a higher priority, this caused Montreal Locomotive works to not be able to start development on the prototype model until the 23 of October 1942 when The Department of Munition and Supply gave permission to commence work on the project. Once Montreal locomotive works started to work with the T35E1 turret they found that it to be too damaged to be useful in the pilot model and on the 6th of November 1942 The Department of Defence gave the Army Technical Development Board approval to return the T35E1 turret for a production M10 turret which costed Canada 22,000$.
On December 2nd 1942 The Department of Munitions and Supply sent a letter to the customs office in Windsor to notify them that the damaged turret would be exiting Canada in the next few days and that they would be picking up a new turret/gun from the Fisher Tank Arsenal.
On the 11th of December 1942 the turret arrived at Montreal Locomotive works and fitting of the new turret happened that day.

The completed pilot model commenced it's first trails at Petawawa at the Artillery School on December 29th 1942. These trails were found to be satisfactory.

The vehicle was then sent to UK for trails/demonstrations in UK and on April 5th 1943 it arrived at 1 BOW aboard the SS Empire Planet. The trails that were done in UK commence of Anti-tank, field artillery and close support role trails, these trails took place at the Royal Artillery's Larkhill school, the trails were completed from the 21st of April to the 5th of May 1943. The trails were conducted by the 17th Field Regiment, Royal Canadian Artillery.

From feedback and criticism from the trails specifically in regards to the slow and difficult to use traverse an auxiliary traverse wheel was mounted and was tested on May 4th 1943 and was found to be useful, but this was a temporary fix as the requested solution was a powered traverse system as they deemed it "essential".

In late May a Logansport traverse system was taken out of a RAM I that was being converted to an ARV and was mounted/wired into the pilot model, at the same time they created an improvised 1,900 lb counterweight as when they were sent the turret, it did not come with any counter weights and resulted in poor balance of the turret. With the new traverse system and improvised counterweight the turret would not be able to traverse at a slope over 10 degrees which they either needed a stronger traverse system or a heavier counter weight.

On the 26th of May Canadian Military Headquarters in UK decided to abandon their attempt to improve the traverse of the vehicle.

UK received production models of the M10 tank two weeks after the 3" S.P. RAM Mk. I was tested and all the defects were found and once the M10 was tested it's performance was superior to the 3" S.P. RAM Mk. I resulting on June 21st 1943 all future trails were suspended and the 3" M10 was to be taken into service.
Due to Canada "borrowing" the M10 turret and gun the Canadian Military Headquarters in England for some reason regarded the vehicle as a mock-up only.

Since the project was never planned to become a fully production model it did not see any other conversions and only had a single example of the vehicle.
The vehicle was sent to the Canadian Artillery School in UK to be used to train drivers and gunners. Up until the cancellation of the project it was still referred to as Project 35

When the project was decided that the project be cancelled it was requested from the Director of Royal Artillery (UK) approached the Canadian Headquarters in England to work on a re-design of the 3" M10 to mount a 17pdr since the British Directorate of Tank Design refused to work the project. Source: https://heritage.canadiana.ca/view/oocihm.lac_reel_c5792/5087

Canada took up this request and developed a working example, which lead to UK picking the project up leading to the creation of the Achilles.

Specs:

Hull specs (RAM):

Weight (fully equipped): 60,000 lbs (Based on M-10)

Engine: Continental Motors Corporation R975-EC2 or R975-C1; Static Radial Air cooled 4-cycle petrol 9 cylinder

Maximum sustained speed on hard road: 25 mph (40.23 km/h)

Expected cross country speeds: 4-20 mph (6.44 - 32.19 km/h)

Maximum grade ascending ability: 35°

Maximum grade descending ability: 35° - 45°

Maximum width ditch vehicle will cross: 7ft 5in (2.26m)

Maximum vertical obstacle vehicle will climb over: 24 inches (0.61m)

Maximum fording depth (not waterproofed): 40 Inches (1.02m)

Crew: 5 (driver, co-driver, 3 gunners (assume gunner, commander, loader)

Armour: (Values may be incorrect a bit as the files are difficult to read)
Upper Hull:
Top plate: ^3/4 Inch

Front bow plate 1 ^1/2 Inches

Back and side plates: ^3/4 Inches

Deflectors (above track): ^1/4 Inch

Lower Hull:

Bow plate: 1 ^1/2 Inches

Side plate: 1 Inch

Rear cover, plate: 1 Inch

Bottom plate: ^1/2 Inch

Turret:

Gun shield: 2^1/4 Inches

Sides: 1 Inch
Top: ^1/4 Inch
Plate, trunnion support: 2^1/2 Inches

Floor (over ammo, compartments): ^3/8 Inch

Traverse: 360°

Maximum elevation: 30°

Maximum depression: -10°

Armament:

3-inch M-7 (55 rounds total: 6 rounds held in a read use mounting at the back of the turret at waist height, 49 rounds stored in a stowage compartment under the floor.) (there were discussions on a modification to the 2 side compartments to hold 24 semi-ready-use rounds Source: https://heritage.canadiana.ca/view/oocihm.lac_reel_c5792/5065)

Fire-rate achieved during testing: 5-12 rounds per minute (Rounds across the board had ejection issues so the real fire-rate could be higher)

Sight: M.51 (American Model)

(optional: A.A. 50 cal. could be added to the rear of the turret as the mounting was there but I was unable to find any photos of it founded
Ammunition:

3" H.E. M42 Fuzed M43A1

3" A.P. M79

(Technically it could fire any round the M10 did however these are the only 2 rounds I could find record of it firing)

Other:

Driver sat on the right-side

Photos:

Spoiler

Sources:
Canada's Pride: The Ram Tank By: Roger V. Lucy (ISBN 13: 978-1-894581-61-5)
Secret Weapons of the Canadian Army By: Roger V. Lucy (ISBN 13: 9781894581400)

http://www.mapleleafup.net/forums/showthread.php?t=5073

https://web.archive.org/web/20180326120506/http://www.ramtank.ca/ram_experiments.htm

RG24, R112, 1996-212 DAP, 1996-02164-8 (https://recherche-collection-search.bac-lac.gc.ca/eng/home/record?app=fonandcol&IdNumber=23639&q=RG24 vol. 151 PA 3)

https://heritage.canadiana.ca/view/oocihm.lac_reel_c5792/5061

https://heritage.canadiana.ca/view/oocihm.lac_reel_c5792/1044

https://www.warmuseum.ca/collections/archive/3133831

Design Record Canadian Developed Military Vehicles World War II Volume 3 Tanks and Tank type Vehicles

https://heritage.canadiana.ca/view/oocihm.lac_reel_c5792/5216

https://heritage.canadiana.ca/view/oocihm.lac_reel_c5792/5173

https://heritage.canadiana.ca/view/oocihm.lac_reel_c8386/3587

https://heritage.canadiana.ca/view/oocihm.lac_reel_c8386/3567

https://heritage.canadiana.ca/view/oocihm.lac_reel_c8386/3562